Lotsa good advice above and I can tell you from having covered multiple PT-40 planes that as planes go it's a pretty reasonable one to cover. We've seen some pure newbies here post pictures of their first covering jobs that look as good as a lot of old-head flyers that I know have been building planes for years. So, you can do an excellent job if you've got a fairly good eye and you put in the effort.

A tip: You'll see lots and lots of talk about shrinking... If you want a good, durable covering job, the ket point is STRETCHING, not shrinking. When you're tacking the covering in place (as AirBear was talking about), if you get vitually all the wrinkles out before really sealing the covering in place you'll have no trouble tightening it up and you'll have no troubles with it loosening later. On a wing, for instance, I usually place the covering and seal it and then let it sit overnight... the next day when I use the gun to tighten it up, it's often hard to tell which panels have already been tightened and which are still to be done. It's actually easier to get the covering on real well like that than it is to shrink it smoothly afterward, so it's a good skill to work on.