If you're playing marauder/warrior, the best thing I can tell you for lower levels is to always have maim up first. I don't know if you're doing that, but the 20% damage boost is also a 20% aggro boost. Spam over power, don't be afraid to run out of TP. Also, don't be afraid to use berserk every time it's up. I guarantee you no one will pull off from you after maim and berserk are on and you're spamming overpower.