Connor,

If you know the branch or specific unit you are going to, look them up online.  See what they do and prepare questions you may have for them.  The questions could be general leadership questions, branch specific questions, or unit specific questions.  Also, take advantage of every opportunity to learn while you are there.  I was able to sponsor a few cadets as a PL.  Some just sat off to the side and never really said much.  When they were allowed to leave, they would.  The ones who had the best experience asked questions, participated in the training, tried new things, etc.  I gave my cadets the opportunity to lead some sort of training or mission, give a safety brief for my platoon, plan some event, etc.  If the LT you are following does not do that, ask if there is something you can do, plan, etc.  Get outside of your comfort zone.  It is your chance to try new things.  If there is something you want to learn, ask if you can do it.

When you have discretionary time, do something other than sitting in your room.  If the unit has something going on, go to it.  Otherwise spend time doing something in the area, talking with the other cadets, etc.

Chad