From what I hear wizards are overpowered. Their attack spells are very damaging.

My character is a knight, and I found the first few levels of his life difficult. Once I got - and started to use effectively - stun and trample I began to find life easier. Stun is nice; it causes the enemy to miss a turn and does respectable damage. If you can then put together some fours you can get multiple turns in a row and hoover up some goodies. Trample is best if you have a lot of red mana; it does damage equal to half your red mana. Later on you get upgrades of these skills.