Any hints for the Disgaea newbie?

Picked this up this weekend along with Katamari Damacy, which makes a tremendous weekend double-bill of gaming, I can tell you. As a fan of Final Fantasy Tactics and Front Mission 3, I’m having a blast with the Nippon Ichi take on strategy RPGs.

I’m still only a handful of hours into it, having just defeated Mid-Boss (great name change, that). I’ve got a grip on the absolute basics of the game well enough, but some of the more abstract stuff still eludes me - the geo stones, in particular, are confusing the hell out of me right now. (At the moment, I understand enough to put a geo stone on a coloured square, so that when I smash one geo stone the other one gets smashed to make a chain.) And the Item World handed me my ass pretty freaking quickly, too.

But I feel like I’m just barely scratching the surface of this game, and Gamefaqs doesn’t seem to have any general overview-type help. Are there any beginning game hints/tips from the Kitsunes in the crowd?

Honda VFR800

The strat guide publisher made a pdf version of their Disgaea guide available for free.

gamefaqs has several articles that are quite helpful. However, their description of what the prerequisites are to get certain classes are slightly off. (I can’t remember how they were incorrect, but I do remember being rather steamed when I found out I had wasted X hours using a lousy class, only to find out that that didn’t get me a desired class later.)