Houndace1: there's a long-winded answer to this one. Not sure I have the energy or the board had the patience to read and put up with me. But I'll give it a crack because you are a great poster.
Okay, three angles:
1. The star freshman. He arrives and maybe feels a bit more important than he should be, especially to the seniors who have put in the time and have the war stories to share with the team. Having ears as a freshman is more important than having a mouth. So, player development for the star freshman is more about emotional and character development. Coaches and senior leaders need to be on top of any outsize ego on and off the field. Drop the hammer on this kid occasionally; call him out in team meetings if he isn't leading an exemplary life. Beat him down then build him back up. Make him earn his role, don't just give it to him.
2. The really good but not good enough to start freshman: here's the kid who will be a star as a junior or senior, but maybe doesn't step onto the field Day 1 as a starter. Make sure he gets real game reps, don't sit him a la Pietremalla/Hopkins and let him rot on a bench; don't let his mind wonder about where he could have played. Put him in games that are tight, give him some real minutes. Get his game confidence up. Encourage him in Fall ball and summer ball to work on whatever you as coach feels he needs to work on. By all means, do not put him on a bench for two years and never let him see the field (like Hopkins...). Adjust his minutes.,..occasionally throw him out with the star on your team. Tell him what he did wrong, but also tell him what he did right.
3. The bench: reality is some guys will literally almost never see time. Their feet got slower as they came into college, something. But that's okay. If they have heart and team spirit, keep them motivated. Talk with them. Let them know they are as important as Pat Spencer, because when you play a game at Lafayette in a woebegone town in front of a small crowd in really cold weather, let me tell you something: those kids on the bench are as important for the starters to see and hear as anything in the universe. And who knows, there is almost always some gem on the bench that for some reason was never discovered, so keep at the bench players, help them develop as much as your starters...they will make your starters better, so it's important that the bench and 'practice' squad always improve.
That's some of player development. (I'll let others describe the stars...how do you develop a Pat Spencer as a senior...harder answer for sure)