Yeah, only play any game from one account at a time. For instance, you could enter the LC on one account one week, then the other the next week, but never to improve your chances of winning. Games like Wheel of Excitement, too, if you wouldn't yet be able to enter again on one account, don't play on your other account yet.
Makes me mad, my second-best account won the gold LC trophy, and my main account only got third
Oh, well, though--I won