I've always was partial to having a leaderboard.
Have the top three in each position group listed with their weight. It tends to be that the starters are the leaders. That's a great motivator for people who want to be starters. Also, if someone is a leader and not a starter, it's either their attitude or knowledge of the game that's preventing them from not starting. If it's an attitude thing, then think about how the younger players will believe it when you give your team rules.