Here's what we did to tackle this project...
1) Measure in an even amount (you choose what you'd want to do, for us it was about 14" on each side) around the entire ceiling. We measured in every foot or so and then connected the dots with a straight edge making a solid box on the ceiling.
2) Prime and then paint the entire square.
3) Then measure the lengths of the painted sides and cut trim accordingly, cutting at 45 degree angle at the corners. That kind of over simplifies it a bit, but that is basically what you do. Tip: 1) Cliche as it might sound measure twice, cut once. 2) Remember, the trim will be stuck to the ceiling bottom side up, so either cut with the back side of the trim up, or remember to angles will be reversed if cutting back side down.
4) Paint the trim pieces.
5) Put the trim pieces up on the ceiling using liquid nails or adhesive caulk and finishing nails. Use a lot of caulk to ensure the trim pieces stick and put a nail in every 6" or so. Tip: 1) We found two length finishing nails at the local hardware store. We thought the shorter ones would have been fine, but that would have been a mistake, use the longer finishing nails to sink as far as possible into the ceiling. 2) Get ready for lots of caulk jokes like "squeeze my caulk", "this caulk just exploded all over", "the tip of caulk is all sticky", etc--have fun with it, because there is truly no escaping them.
6) Using a paintable spackle, patch nail holes and trim piece seams.
7) Paint over spackle. (We actually haven't done this part yet, but it is next on the list!)
Check out the cool new ceiling fan too!
Just a few more finishing touches and the bedroom will be complete and I'll post all the "after" pictures!!