Here are some of the ideas I would like to try:
Kill the enemy by poison and creature swarm
Weaken enemy creatures and and beat them up with my buff mage
Try to control the enemy's movement through spells like Push and then sling attack spells like I have a fireball throwing machine gun
Oh, and winning. That sounds like fun.
Any tips are appreciated.
I can recommend winning. It's really good!
Also, the best tip for this entire game, which I always try to adhere to myself (not always successfully):
ROLL WELL
Seriously, the best designed book in the world, handled perfectly, can still lose to a piece of rubbish if it rolls badly and the rubbish rolls well. Getting 3 damage from your 13-dice attack? Lose the game. Opponent gets 15 damage back from an 8-dice Heal? It happens.
(This comment may sound trite and may be a bitter reaction to what happened to me in a game recently)
Seriously, though:
Step one for designing any book: Consider how you are going to get those attack dice onto your opponent (lots of little creatures? a few big creatures? attack spells? pushing them through walls? buff your mage and charge?)
Step two: Consider how you are usually going to avoid having your opponent's attack dice getting to you (armour? defences? enchantments like Block? using creatures to guard? hiding behind walls?)
Step three: Consider whether there are any types of Mage that your choices in Steps one and two will be weak against, and what options you may need to include for those situations.
Step four: The metamagic game. How are you going to get rid of the opponent's enchantments and equipment. How are you going to ensure they don't get rid of yours? (nullifys, dispels, dissolves and so on)
Step five: Are you going to assert any board control and have freedom of movement (pushes, teleports, walls, tanglevines)
Now just try to stuff all that into 120sbp in a way that your expected mana supply can maintain turn on turn.
Oh, and practice, practice, practice...