What they said. Another tip: pass the ball a lot. This helps get your guys experience, which is important. You don't want one of your players falling behind in levels, or his stats won't be able to compete with the other team's. So try to get experience for all your guys, if you can. The best way I've found to do this is using Tech passes. You get more xp for completed tech passes, whether you're being defended or not. Also, the higher the version of the tech pass, the more xp you get from it. Like I think you get 3 xp for each completed Venom Pass 2, and 2 xp for each completed Venom Pass 1. You get even more xp if your pass (or attack tech, for that matter) effects another player. Like if you use Venom Pass 2, and it poisons your defender, you'd get even more xp from that. Passing also helps you advance the ball toward the goal. If you don't have confidence in your guy's ability to break through defenders or pass past them, pass the ball before a defender gets upon you. Which also brings me to this:

Know your guy's stats and abilities, and the other team's. For example, know if Botta has enough Endurance to get past their forward's attack. If he doesn't, you'll wanna know if he has enough Passing to get past their forward's block. Don't forget that some techs add to your passing skill, so you can factor that in. And, if you have a player that has lots of endurance or passing skill, you can use him to draw off two or more defenders to open up one of your guys! Here's another example: my Letty has really high passing skill. Much higher than the BL ability of anybody on the other team. Combined with Venom Pass 2, his PA ability is that much higher. So, since he can pass through a couple of guys and still complete the pass, I'll have him swim around one guy and get his attention. Then I'll have him swim around a player that is guarding the guy I wanna free up, and get his attention. I'll have two guys then swimming after Letty, which will make, say, Datto wide open for a shot.