If you want to level up fast in Wizard 101 you have to complete as many quests as possible. Best quests are school quests (like from Headmaster Ambrose) or search quests (like the smiths, beetles and yardbirds). Battling doesn't give you as much XP as quests.
Another way of leveling up quickly is to join up with a friend who's got an account with a high level character. You gain XP very fast by completing quests which would be too difficult for you alone.
Wizard 101 cheats for leveling up videos:
There are no concrete "cheats" for leveling up fast in wizard 101 at this time!