Definatly use supplements they really help you gain quicker and work through plateus
I am a Junior right now I play football too so I know where you come from
Most ppl on this forum swear by creatine i personally have used it -you have to stick with it just like anything else when it comes to weight lifting
I use protein because my coach would hang me if i used creatine
He is the safer than sorry type no long term study possible kidney problems w/o proper hydration etc.
Creatine use it but be smart and stay hydrated
http://www.angelfire.com/extreme/weightlifting/charts.html This is a 1 rep max chart /You may have acess to it at school for football i do/it shows you what you should do on ur sets based on a 1 rm
i think that is something that should help u