The most important thing is to look for good straight-growing trees (ie - no wind twisting). It should be easy to tell by looking at the bark. I will defer to those dedicated self-bow builders we have here as I have only built a hand full in the last 5 or 6 years.
The care and preparation for curing the wood can be followed on several threads in the archive.
I would suggest though, if you decide to fell a tree, its not that much more difficult to do a whole slug of 'em! That way, when you really get addicted to making shavings, you'll have a generous supply!
Stacker