Any tips for someone headed to their first unit?

Also, read up on Infantry Rifle Platoon and Squad ops. When I was in it was FM 7-8. Now it looks like it is ATP 3-21.8. It is heckin simple to get Army Regs and Manuals nowadays. Get 'em, read 'em.

https://armypubs.army.mil/epubs/DR_pubs/DR_a/pdf/web/ATP%203-21x8%20FINAL%20WEB%20INCL%20C1.pdf

Don’t buy a brand new truck from a dealership close to your duty station

Don’t get married!!!!

1. Take care of your body. Within reason, do not let people get you down over going to sick call. If your back hurts, absolutely do something about it. Despite the mantra from Basic, pain is not weakness leaving the body. It is your body telling you that something is wrong. Know what the pain means (lactic acid after workout, or sprained ankle, or slipped disk?) and do something about it.
2. Save everything that you get. Find a notebook, it doesn't have to be anything fancy, and you don't even have to put things in there in order. Just start putting things in there. LESs, Leave forms, Counseling statements, NCOERs (some day), award certificates, deployment orders (important), anything you can get your hands on. You cannot count completely on S-1 for this, you need to count on yourself.
3. One of the unstated truths to the military is that when everyone looks the same (uniform) those that do not get noticed. This can be bad, and it can be good. Lost in a company of Infantrymen with AAMs and ARCOMs? Find some way to get something they don't. It didn't happen when I was Infantry, but eventually I got a Navy/Marine Corps Commendation for working with the SEALs. That set me apart. Get noticed for things like that.
4. Save that money. Do not be like I was. I was on Schofield. I spent all of my money every month of stuff that was completely temporary and necessary. Being on Oahu, you do not need a car. Wahiawa is only about 2 miles away, you can take the bus (52 still goes on post?) or walk, it is not that bad, and that is one of the good things that I did. Save that money, you will definitely be glad you did.
5. Inform your NCOs. There are things they need to know. You purchased a car at 25% interest. Tell them. You did not get paid what you think you should have (LES cam in and you have $600 deduction that says Separation Pay?) Tell them. Your NCOs are there not only to lead you, but also to help you navigate your way and not screw yourself up. They *should* provide you with guidance, and sometimes some authority by way of accompanying you to wherever you need to fix the problem.
6. As an Infantryman, Shoot, Move and Communicate are absolutely the must-know things. Don't settle for Marksman. Study up on Land Nav (the ability to accurately read a map is very important). Learn how to communicate precisely and competently over a radio network.
7. Waist Belt. When I was in, we used the ALICE ruck sack. There was a waist belt that was never to be used on your waist. Instead it was wrapped backward around the frame and often we used sleeping mat pad taped to the frame to make it more comfortable. The shoulders of a human are not designed to carry very heavy loads. The waist is. Your back and shoulders will thank you for it 20 years down the road. If the pack has a wide web belt at the bottom, use that around your waist. Let the hips carry the load, let the shoulders keep it upright.

First impression to every NCO: PARADE REST and address them by their RANK. (A corporal is not your ‘Dawg’ or whatever you kids are saying now)
Believe it or not no one will be impressed by your OSUT unit, what you did before the Army and who your Sensei was. We went through the same Basic that you did and your Drill SGT was no more frightening than any of ours. No one who was in a day longer than you cares that you were Platoon Guide and will not hand you their rank or give you their leadership position.

Most importantly!!! Do not be the FNG that hangs out with the chapter cases or the FNG that got drunk and went to the hospital/jail his first night/weekend.

When I was at Schofield (A hundred years ago, it seems) They offered a few college courses per semester for free that was taught and accredited by UH professors. They came right to the day room and provided all the books etc. all one had to do was sign up and show up. I only took a couple of courses, but a guy I graduated AIT with took them all and left Oahu with an AA from the University of Hawaii, all for free. Get the free school!!

Start a 401 K. Don't be too aggressive, just something you can stick with and not touch. Retirement seems a long way away now, but it'll creep up on you. You'll be stoked to see your retirement account in 20 or 30 years.

Get a surfboard. It's great exercise, doesn't cost a lot, good to help you clear your head after a hard week.

Work out, work out, work out. As much as possible. Make that your go to time sink. Not just gym rat stuff, go running, swimming on post, hikes, anything you can do to build strength and endurance.
Study, study, study. Every relevant TM and FM you can get your hands on, the ranger handbook, the post guide, your unit's history. STUDY EVERYTHING. My personal unicorn, a PV2 who can rattle off a perfect 9-line, be that PV2.
Disregard strippers, 32.2% interest rate mustangs, and buy here pay here anything.
Use your TSP, sock some money into a CD at the local credit union.
Correspondence courses, start racking up college credit, the GI Bill is a great tool for after the army.
Learn who the mentors and the leaders are in your company, ignore the ****bags who are going along to get along.

And most importantly, have fun when you can. The first duty station and the first enlistment sometimes suck serious amounts of garbage, but even then you can still find the bright side.

What everyone has been saying has been good info but one of the biggest things I noticed between the new guys that people liked was

1. Be good at PT (Obviously)
2. DO NOT try to force camaraderie!

When I got to my unit, I kept my head down and let my actions speak for me. I allowed myself to slowly integrate and let my squad accept me in as they got to know me. Don't act like one of the boys when you don't know anyone there.

Versus kids who would show up on their 2nd day and greet the at the guys at the smoke pit with "Whats up motherfuckers?" those are the guys that got on the shit list fast and remained outcasts and shit bags for most of their time at the unit.

God gave you 2 ears and 1 mouth. Listen twice as much (or more) than you speak.
Let your leaders lead. You know about 1% of what you need to know right now, be a sponge.
Learn your units SOPs. Learn your units history.
Echoing....find a good mentor.
If you have to look over your shoulder before saying or doing something, don't do it.

Be calm, stay collected and listen more than talk. Be an outstanding learner and listener, do your work to the best of your knowledge and abilities, know what is expected of you and never shy from questioning what is unknown.