If you play Wizard 101, there are a few things you can do to make combat work a little better in your favor.
First, choose your deck wisely. Rather than having to rearrange your deck every time you face a different opponent, just keep a variety of decks in your backpack. At the very least have a secondary deck so that if you are fighting someone from your school you can use some alternative spells. Then, depending on what school you are fighting, switch to the deck required....