What do I need to do to prepare this trunk for painting?
First you need to remove the masking tape and the label prior to painting, or they will show through on the finished surface. Use Goo Gone or Goof Off as BMitch and Tester suggest. (I've never used Goof Off, so I can't vouch for how well it works, but I have firsthand experience on how well Goo Gone works.)
Next you need to clean the surface, at least with a damp cloth. Let it dry.
If you really want a clean edge for the parts you're not going to paint, you can use blue painter's tape to mask it off.
Next, prime the surfaces that you are going to paint. This will help the paint adhere to the trunk and reduce the chance of the paint peeling on down the road.
Finally, paint. I use latex for most of my projects, since it's easy to clean up. Pay attention to what type of finish you want. A roller will give you a slight orange peel effect, while a brush may leave brush strokes. If you want a smoother finish, you can add some Floetrol to latex paint to minimize any brush strokes. Buying a high quality brush can also help. You may have to do several coats of paint, but I'd do a minimum of two.
If you used painter's tape, carefully pull it up. If you have problems with the paint sticking to the tape, gently score along the edge of the tape with a razor blade.


I wouldn't bother painting the bottom.