Don't sand the basecoat.
The nice thing about base is that it is easy to remove if you really bugger it up. Some lacquer thinner will take it off. To all those who fear painting, base is really easy to shoot. The clear is where most problems occur.
Basecoat do's and don'ts: Shoot for coverage, don't flood it. It will look crappy and dull, but the clear fixes that. Never sand basecoat. Shoot a drop coat for metallics to even it out and avoid tiger stripes.
Clear: The tech sheet should tell you when you can sand/buff. Most are pretty fast so shops can get them out the door. I waited a few days to be safe. Be REAL carefull of edges and proud rivets. Keep the pad tilted and running off the edges. (another "oh ****!" lesson!)
autobody101.com is a good place for general info.
Practice, practice, practice...but not on your plane. Junkyard trunk lids and hoods are good practice fodder, but you might have to sand down crappy factory orange peel first!