What is the best way for a new 2LT to counsel a platoon sergeant?

Find out about his family and education background from his personnel file and then slowly begin discussions with your platoon/squad etc.

Why on earth would a 2Lt attempt to council a PSG? The 2Lt is there to be trained, He doesn't get to council the trainer.

Get advice from the First Sergeant, consult UCMJ.

hahaha... given the butter bars I worked under as a Platoon Sargent... a 2Lt should NEVER come off as anything less that a ROOKIE with NO experience or knowledge of REAL MILITARY LEADERSHIP.
2nd Lt's who get in the face of their experienced Platoon Sargents can expect an attitude...
especially if it undermines the authority of that Sargent with their soldiers.
Platoon and Squad Sargents claims responsibility for their soldiers, and will be ROYALLY pissed if that Lt gets that Sargent's soldiers killed with inexperienced stupidity of "I AM IN CHARGE - DO WHAT I SAY!"
Too many good soldiers die needlessly because some new officer has an I AM GOD power complex >(
John Wayne Lieutenants die early, and needlessly... and take soldiers that would have lived with them. LISTEN TO YOUR EXPERIENCED NCOS!!!
Throwing bodies at a machine gun nest to get a posthumous medal is STUPID!
Throw grenades... rockets... air strikes... NOT BODIES!
Bodies only stop bullets... and die.
for the record... I never had an issue with a 1st Lt... only the golden bar heroes.
If you live to be a 1st Lt... you'll have it figured out who is the Sargent, and who is the leader ;)
My worst CO was a Captain who never got past leading as a 2LT...
Thank you for your service Captain Arron.
RIP

Unless there is a flagerant violation of some regulation, the 2LT should observe the SFC's behavior and actions and if the 2LT believes there is a violation of anything, seek council with the Company commander before engaging the SFC. The officer has theory and the SFC has practical application. There is a happy medium between the two. If we are talking career paths and military education, the 2LT can sit one-on-one as someone who is 23 years old, and ask the 32 year old SFC what (s)he can do to help him get to the SFC's objective.

They dont need to.lead more yhen themselves for atleast4 years. How many have gotten soldiers, marines, sailors and air force personale dead. They need more then college. It blows my mind going to college makes you a better soldier. What a joke. How can they still think this sfter 300 years?0

Very carefully

The 2nd LT should listen closely and take the suggestions of the platoon sergeant. The sergeant got to that position by performing well, and unless the sgt is breaking some reg or other misconduct, learning from him is the best thing to do.

I’d have a private conversation with the 1st Sargent, then do the paperwork and either have the 1st Sgt there or maybe the Captain.

If you’re a second lieutenant and you have an NCO that you think needs counseling. Be very careful. You may be right, you may be in the right, but it’s gonna be very easy for you to screw this up. I hope you have other officers with a little bit of time under their belt that you can go and talk to them and talk this out before you start this counseling session. Remember this NCO deserves the respect of his or her rank just as you do. Any counseling session starts with a clear list and understanding of what you want to talk about and what you want to retrieve before you even start the conversation.