When you practice a play, you can level it up and decrease its stamina cost and risk. To do so, wait for the arrow above the receiver to turn green, then slide towards him. If done correctly, you should earn a "PERFECT!" rating. Each time you get a "Perfect" rating, the play will level up. When first starting, level up all of your available plays at least once. Getting them to level 2 decreases the stamina cost by 5%, allowing you stay in the game for a longer period of time.