The more you play, the more you get. The better class of opponent you play, the more you get. The more you beat higher ranked players, the more you get.
Playing games = more xp = more levels = more points for your players = better players = better team = more winning games = more xp, and repeat. To put points onto your players if that's what you mean, just go onto your team page, and click the tactics section, where you can choose each player and put points on each one.