I tend to comment about the moves everyone made each year as good, bad, great or ugly and why. If they were bad, I talk about the strategic implications of the moves I WOULD have done. I rank each power in their respective spheres and state why, and if I make any claims for the future, they're vague like
"As I look at X's present course (not specifying his present course) I see that some considerations need to be made to ensure future builds, even if it means a large structural change." Etc.
As long as professors aren't stating things like "Germany's best bet going into this next year is to break off his current fruitless alliance and siding with the Russian" because it's influencing the game in the way it isn't meant to be done.
Players should understand that their TA is their best asset. Not professor posts because we see only the moves. We may assume some of the press based on these moves, but your TA should have huge insights that we do not. As a TA, I would always allow my player the final choice on everything as I helped him see his options.
Players should be sharing press and their ideas with their TA.
My recommendations on how to TA: when I TAd for a player, say Italy, I would ask for his press and help guide him into reading through to determine who is telling the truth and lying and ask him what he plans and how he responds. If I didn't like his move choices, I would simply ask him things like "and might your enemy do here. What if he moved like this?"
I try to allow the student to develop the best way forward on their own instead of me telling them how to move. Early on, I'm more prone to do more of the driving but always getting them to look at the bigger picture and how to put themselves in their opponents' shoes to determine their own moves.