I paid $25 for someone to braid mine for a show :) So, if you practice enough, and get good enough, you could actually make some money at it.
I trim his mane to about 4 inches, wash it, and keep it wet while I braid. I also use Quick Braid, which is like a hair spray. I've heard it's important to pull down as you braid, as this will help keep it from sticking up. Also, stand on a bucket so that you're eye level. I have a little comb that I've broken off to measure 2 inches, and use that as a guide for each braid. I braid all the way down the mane, and then go back to do the buttons. I fold the braid underneath itself,
(take the bottom of the braid all the way to the mane), fold it again, and attach the band. I'm still practicing with the thread, as I feel it does produce a better braid. I also noticed he's more sensitive near his withers, but eventually I get it done. He doesn't have much of a forelock, and it causes me the most trouble, but once I'm at the show and I see everyone else's braiding jobs, I don't feel so bad.