If you need to solo a boss you may want to try these things to help.
1) Pop in and out of the boss' lair to see what school it is.
2) Set up your hits in your main deck and clear your treasures
3) Go to the bazaar and buy 1 pip dispels for the boss' school (about 4) and put them in your treasure
4) Buy the highest protection shields you can get for the boss' school (about 6) and put them in treasure
5) Buy treasure tri-blades for your school, (if you haven't learned the tri-blade for your school from Nigel in Krockotopia... hurry and go learn it)
6) In your main deck, pack a couple shields for the boss' minion's school
7) Use the dispels only when the boss gets power pips or 6 + pips ready
8) Pack several heals
9) If you have a pet with spritely and or shields equip it! I'd take a pet with spritely before a pet with shields.
10) Blade up as much as possible for your largest Damage-Over-Time spell. For fire this is heck hound. For Ice it's ice angel, Death - Death dragon... for Storm well... you generally won't need a DOT but you can use storm hound for fun. Myth is pretty much set with puppy or Medusa. And for Life it's pretty much Forest lord for the first pass and some well set up centaurs.
I'll try to post some specific guides for dealing with certain cheats. For example some bosses cast Efreet on everyone and you can dispel that with inexpensive fire dispels even though the boss casting it is ice. It may seem like cheating but why not take a little advantage for yourself against a boss that's cheating you?
Does anyone want to share their tips for beating their school-pet boss?
Enjoy surviving with creativity!