Gameplanning is the way to teach your players new plays. You have to teach the players the plays or else they will mess up and you will lose. In the preseason, you can only choose to work on one player or play. In the regular season, a whole bunch of new choices pop up. You are able to work on different sets. One choice might be "Work with OL" or another might be "Improve Shotgun plays". I normally choose those because they increase play knowledge for more than one play.