I see you've found the Best Tips thread, if I read between the lines correctly...
General thoughts:
1. Get spell schools to level 7. You can train these in the guilds, so train there whenever possible. You can do that once per level.
2. Don't switch classes until you've got those level 7 spell skills, unless you really don't care about them. Other spell levels you can learn as other classes, but not level 7. Leastways, not until you're an advanced Zenmaster, that is... and by then, the game is practically over.
3. That barbarian massive hitpoint thing? It doesn't always work out...
4. If you've got two wizards, let one master in sun and the other in stone. They can pick up the other school later.
5. IF you have to pick one wizard school to start, make it stone. You can't learn that again until you're a zenmaster...
6. When possible, put skill points in skills that you can't train in at the guilds. And go for the skills near the end of the list first; they'll disappear in a bit, never to come back. Radek will argue with me, but I don't see the advantage to putting 'em in sorcery early on. And he knows best
That all being said, have fun! There's no right or wrong way to play, only choices you make...