What is the proper way to address NCOs in different branches?

Generally by their rank and last name.

They (Marines) do NOT call "them" sir. You do NOT under ANY circumstances call a Marine Sir / Mam if they are not an officer. We work for a living. An E-7 would be called Gunnery Sergeant or Gunny. When in doubt address them (any military member) by their rank.

How about "Listen up Fuckers!"

In the navy you call e-7 and above chief, senior chief, or master chief. E-4 to E-6 petty officer is okay. Although most would prefer to be called by their rate. For example AT2 or AD1.

You address any NCO regardless of the branch at parade rest, followed by their prospective tittle. If you’re talking to an E7 (Marines), you refer to him as Gunnery Sergeant. Regardless of the trolls, if you are lower enlisted, (NON NCO) every NCO in the Armed Forces outranks you and deserves the respect they’ve earned by achieving the rank of an NCO.

Stop calling yourself an E-4. THAT is a pay grade and not a title or a rank. You are either a CPL or SPC in the Army. Call people by their proper rank in other services until they correct you.

Saying "Hey fucker!" while using a knife hand usually works... but I only recommend this to Veterans. Anyone in active duty is sure to get them ass reamed.

The reason you hear Recruits in USMC Boot camp address EVERYONE as sir and ma'am is, they haven't graduated Boot Camp yet and they are instructed to address everyone as Sir or Ma'am.
Once they earn the Eagle Globe and Anchor , only Officers, Warrant Officers and the general public are addressed in this fashion .
It is part of the Marine Corps. Customs and courtesies.

There are plenty of charts on the inter webs about rank structure. As a Marine I know all Army and Navy ranks as well as ours. I don't know the Air Force ranks very well but I don't not interact with them. If you plan on being a career Soldier, Sailor, Marine or Airmen it is not a terrible idea to learn them all. DoD is a joint venture and as such you will be working with all shapes and sizes.

This should be required learning for every recruit while still in boot camp, maybe handed out on a small wallet card, etc. Knowing these simple protocols will go a long way in showing respect and knowledge to members of other branches and will be greatly appreciated by someone when their rank and position is correctly referred to rather than unknowingly butchered by someone of another branch.

Recruits are required to call their Drill Instructors "Sir". But after boot camp all enlisted marines are addressed by their rank

Personal experience: As a Marine, I was trained to use full rank. I was on an Air Force base for tech school and even though I didn't have to, I used full rank. The AF NCO's seemed to really like that.

I started out as an enlisted soldier in the Army. We only addressed officers as sir or ma'am. The NCOs, we called them Sargent from E-5 through E-8, unless you were a First Sargent. E-9s were addressed as Sargent Major. We didn't dare call any enlisted sir or ma'am. When switched to Air Force, I was shocked to hear the enlisted being called sir or ma'am. Being that I am a soldier airman, I call the NCOs Sargent, E-5 through E-8. The E-9s I address as Chief. I never address any enlisted person sir or ma'am, only by their rank.

Recruits address every Marine enlisted or Officer as sir or ma'am until they have earned the title of Marine. After they have become Marines they address fellow Marines by their rank and last name.

Recruits in Marine Corps boot camp call everyone Sir. If they didn't, they would be destroyed by their Drill Instructors. Once tte Recruit earns his Eagle, Globe and Anchor, they call eeveryone who is a higher rank than them by there respective rank. As a soldier addressing a Marine who is higher rank than them is the same way. It's all about respect. Marines do the same thing.

Marine recruits use sir to address an any Marine only in recruit status. Once Marines earn their E.G.A s they are taught to address Marines by their rank or rank and last name. In the Marines we usually just learn the ranks of other branches to make fewer headaches in the future. At first it can be some rough seas not knowing the ranks but after a while you have issue addressing any service member by their correct title. Even foreign troops.

I didn't realize Gunney was a "only when you know each other" kind of term. Thanks for the lesson on that.
I remember working in an office setting with two Army E7s (SFCs) when I was a 1LT. They always referred to each other as Sergeant Jones and Sergeant Smith. I finally asked them..."If I wasn't here, would it be Jill and Melissa" (I used their actual first names when I asked the question, but I don't remember them now). They told me yes. I thought that was interesting.
I worked very closely with a CW3. He was adament about being called Chief. We'd occasionally get soldiers from other units in our area who were not sure what to call him and they'd start with Sir. He always told them (in a fatherly way, not a butt-chewing way) that the LT (me) was Sir, but he was Chief. His other peeve was when he'd hear of a WO1 being called Chief instead of Mr.

A Marine recruit is not a Marine. In fact, a recruit is nasty, worse than a civilian because they have the audacity to aspire to be a Marine. Therefore they address all as sir or ma'am.
Once a Marine actually becomes a Marine, then enlisted Marines are addressed by rank.

Years ago when I was and army E5, I was assigned to the ID card section. A USMC Staff Sergeant came in to get an ID card. I addressed him politely as 'Sergeant' and he proceeded to correct me in a very derogatory tone, "that's Staff Sergeant'. Now I was a good NCO being respectful in my office. Perhaps I should have know how to properly address this NCO, but I made a mistake. I felt his tone was out of line and within moments my system 'crashed' and I could no longer help him. Moral of the story: do your best and be respectful and if you do make a mistake, the other party should have the decency to either let it go or politely correct you.

Correct me if I am wrong, but I think that in training, the cadre are called sir by the trainees.

Back in the day - 1990's - when I was a Gunnery Sergeant, shortly before I retired, a sailor on board the USS Nassau called me "Sarge" .... I leave it to your imagination as to the response - and he was a Senior Chief.....

If your looking at a senior NCO, it's by Title. But if your looking at E4-E6, the naval ranks (Coast Guard and Navy) are the most difficult since they don't have a rank like Sargent. Instead they identify rank by position. So if they are a cook you'll call them one thing, and if they are a cryptanalyst, you'd have to call them something else. A simple what of addressing them is calling the Army, Air Force and Marines as Sargent and the Navy and Coast Guard by Chief until they correct you. Then call them by the title they tell you to address them by.

Also remember, there are two other services, US Public Health Service and NOAA. These services don't have enlisted, but their officer ranks are the same as Naval Ranks. You should address them as such.

You address an E-7 in the Marine Corps as Gunnery Sergeant. There is no other officially authorized term of address. Unlike in the Army where you would call an E-7 Sergeant in address and Sergeant First Class or Sergeant when talking about them in 3rd person...

Address them as Gunny Sgt., MSgt., Chief (Air Force, Navy, Coast Guard), etc.

Lol, you call a Marine E 7 properly as Gunnery Sgt, especially being out of unit. You know him he’s Gunny.

MC E7 is Gunny, I’ve never heard of anyone ever getting bent about that.

I was Army stationed on an Air Force base one of my boss' was a gunny.

The DoDI (50110-04-M) has the way to address each rank of each branch. The Salutation for a written letter corresponds to the service etiquette of verbal address.

https://execsec.defense.gov/Portals/34/Documents/511004m_v2.pdf?ver=2013-03-02-045134-443

By their rank!

Marines: Full Rank, according to MCO 5060.20. It wouldn't be a bad thing to call him "sir" out of politeness unless he's extremely salty. Gunny and Gunnery Sergeant are preferred forms of address for the GySgt.
Army: SGT - MSG may be addressed as "Sergeant" or by their full rank, according to AR 600-20.
Air Force: SSgt - SMSgt may be addressed as "Sergeant" or by their full rank, according to AFI 36-2618.
Navy is a little different. Petty Officers from 3rd through 1st class are referred to as "Petty Officer" or by their rating ("CTR1" for a Cryptologic Technician Receiver 1st Class Petty Officer). Chief, Senior Chief, and Master Chief Petty Officers are generally referred to as Chief, Senior Chief, and Master Chief respectively. The Coast Guard, PHCC, and the NOAA, since utilizing Naval Rank structure (though some do not have enlisted, like the PHCC and the NOAA), follow suit.

I would say By Short Tittle...

I’ll admit I was in the wrong in the following situation.

I had to go to al Assad air base in Iraq to train some marines. Cool fine whatever. I had an e-7 marine talk to me and I said Roger sgt. He then tried to chew me out and force me to call him gunnery sgt snuffy. I said Roger sgt. If he would have been polite and respectful, I was an nco and in the army, I would have done things differently

The E-9 Marine told me to just call him Top. I said that works for me.

For the Navy it's Petty Officer then Chief, Senior Chief, and Master Chief.

Just do what I have always done. I ask them what is their rank. It has worked well.

So, fun story. I’m a Marine that has switched to the Army. My last rotation we had a Marine unit stationed with us and my LT was the middle Man in dealing with them. This guy would constantly come to me “SGT Baswell, how to I talk to Marines” “ SGT baswell, why when I saluted a Captain in the field did he look at me like I had a dildo attached to my head”
It was fun to watch..

Also on the flip side, I came into the Army with no “welcome to the Army” OSUT or anything just arrived at fort hood grabbed a uniform and poof soldier. So SFC comes and asks me a question, and I accidentally called him gunnery Sgt. And was looked at weird. Definitely takes some getting used to with the culture shock

In the Old Marine Corp, Cpl's are to be addressed as Sir by all other branches of service in the world. For example: Marine Cpl, "Are you eye ****ing me?" Everyone in the world, "No Sir!"
Have a great Marine Corp day. I'm having one.

As a former US Army NCO and having worked with all branches, fall back onto what you were trained to do. When I worked with USMC Recon at Onslow Beach, Camp LeJeune NC we addressed the company gunny as SGT. His having done joint training before, he expected it. His marines about lost their shit over it though.

I do have one good statement as a Sergeant First Class (E-7) I was at an U. S. Air Force Medical Center and the Tech that called me up and called me as a Senior Specialist. So at that I corrected the individual. He was very happy to informed of the correct rank.

I work as a civilian in a Navy facility where there are both active Navy and active Marine personnel working daily. The Marines are very particular about it and expect to be addressed by their full, correct rank even by civilians. Don't take shortcuts there, even an E-3 in the Marines will be insulted if you get it wrong or don't use it because they feel that they earned it.
All the other branches I have worked with are much more laid back and the Air Farce is almost like being a civilian with regard to rank. They really do call each other by first names.
It is best to use the rank until you know how the individual feels about it.

When in doubt SGT or Sir are both respectful. They will correct you if you get it wrong. I had troops that switched to Army from Marines. Their conditioning meant that I was called Gunny pretty regularly. I was not offended, I just had to keep reminding them I don't eat crayons.

In the Marine Corps:
E-4s & E-5s are referred to as Cpl or Sgt
E-6s are referred to as Staff Sergeant
E-7s are Gunnery Sergeants but, if they if they allow, you can call them Gunny.
E-8s are either 1st Sergeants or Master Sergeants. At the co level the 1st is usually the senior enlisted and may be called Top.
E-9s are either Sergeants Major or Master Gunnery Sergeants. A SgtMaj is referred to as "Your Holiness" and a Master Gunnery Sergeant is referred to as "Your Majesty" with the appropriate bow rendered!

In Vietnam at 35 years of age I was one of the older First Sergeants in the Battalion. I was aware that even the Battalion Officers called me "Pops" behind my back. Secretly I kind of liked receiving the questionable respect for my age but had anyone said it to my face I may have invited them out behind the "hooch" for lessons in etiquette. When I worked closely with troops long hours of the day I had no qualms about being call Top or Sarge. It is easier and shorter than the title of First Sergeant therefor more efficient. I expected Officers and NCOs senior to me to call me by my rank as I did them when I addressed an Officer or NCO that was my senior. I think judgement of each situation is called for rather than written rules or regulations. Sometimes rigid rules can cripple a unit and prevent good judgment from prevailing.

In the Navy between E-6 and below on ships anyway it was last or nickname, we didn't say "hey leading petty officer" And E-7-E9 was their rank, CHIEF, SENIOR CHIEF, MASTER CHIEF, mostly but often their rank and last name. Now if you heard someone calling you by your rank and last name, that usually wasn't a good thing. Heard a sea-story once about an Ensign & a Master-Chief, supposedly, the Master -Chief was at a shore station eating lunch at an outside patio with some others, when he stood up and started walking away an Ensign walked up to him and said "Excuse me Master-chief but I believe you owe me a salute." to which the Master-Chief replied by taking a Quarter out of his pocket and flipping it to the Ensign "Here's a Quarter go tell you momma you met a real Sailor." Did it happen??? I don't know I wasn't there. Does it sound like it could have happened? Yes I can see this easily happening. It's funny when you think about addressing Officers, you can address them by rank or rank and last name, but a Lieutenant is almost always L.T. and of course in the Navy the CO. is always addressed as Captain regardless of his actual rank.

Navy is petty officer or chief/Sr chief/Master chief

By rank for Marine Corps. I did not like "top" Master Sergeant worked for me

Not really the answer to this question, but the following should shed light on how things really are:
The Image of Rank

General:

Leaps over tall buildings in a single bound, is more powerful than a locomotive, is faster than a speeding bullet, walks on water, and gives policy to God.

Colonel:

Leaps over short buildings in a single bound, is more powerful than a switch engine, is just as fast as a speeding bullet, walks on water if sea is calm, and talks to God.

Lieutenant Colonel:

Leaps over short buildings with a running start and a favorable wind, is almost as powerful as a switch engine, is as fast as a speeding b-b, walks on water in an indoor pool, and talks to God if special request is approved.

Major:

Barely clears quonset huts, loses tug-of-war with locomotives, can fire a speeding bullet, swims well, and is occassionally addressed by God.

Captain:

Makes high marks when trying to leap buildings, is run over by locomotives, can someimes handle a weapon without inflicting self-injury, can doggie-paddle, and talks to animals.

First Lieutenant:

Runs into buildings, recognizes locomotives two out of three times, is not issued ammunition, can stay afloat if properly instructed, and talks to water.

Second Lieutenant:

Falls over doorsills when trying to enter buildings, says "look at the choo-choo," wets himself with a water pistol, and mumbles to himself.

CADET:

UNAUTHORIZED TO DO ANY OF THE ABOVE WITHOUT RTO/BTO APPROVAL, BUT BE READY TO ASSUME THE JOB OF GENERAL IN A HEARTBEAT.

An NCO:

Lifts building and then walks under them, kicks locomotives off the track, catches speeding bullets in his teeth, and chews them, and freezes water in a speeding glance. He is God.

In the USAF if you don't know the individual, you would address them by their rank. Tech Sergeant Smith, etc... Once you know them and have a rapport, you could call them by their first name unless in a formal function... Then stick to rank to keep it professional.

Boot camp is entirely different. Using rank is always appropriate. Other "nicknames" like Gunny or Top are also OK.

When in the Air National Guard, as a Chief Master Sergeant, I was always called Chief. Because I was in fire protection as fire chief of my department, I was 2 or 3 times called Chief, Chief, which I kind of got a kick out of.