The hardest Clique to fight is the Jocks, go after them first. You'll need a fresh Russell to pound on them. Make sure you take away the bats from the Jocks who have them so Russell can use one or just so that he doesn't get ganged up on.
Next go after the Preps. They block and dodge like crazy, so go into your boxing mode (dodging and counterattacking) to knock them down. If you have to, take out Derby using your Hobo moves, then rush in on the Preps attacking Russell.
Third, take on the Nerds. This will be a good break, but watch out. Sometimes, one of the Nerds will be carrying a bottle rocket launcher or a spud gun. The other will usually have one of the weaker projectiles, while Earnest himself has a yard stick.
Finallly, fight the Greasers. The only real threat here is Hal, who can give Russell a run for his money much like Damon from the Jocks. Beat Johnny off and take Hal down first, then beat the Greaser leader. After doing so, help Russell with the final baddie.