Most importantly, start with a vision of what you want to do. If you don't imagine it, you can't keep yourself heading towards the end result.
Next, you need to put your vision on paper - I did it a few different times. Sketching randomly, identifying the challenges, and mentally testing different solutions.
- plan, plan, plan (including where you'll get or borrow a mitre saw and a nail gun)
- remember that the saw will eat up some of your length, so double check which side of the line to cut on
- I aimed to cut 1/8" over what I had measured - I found it was easier to trim it down a bit than to have cut it too short. If you can get it right on, rock it... I wasn't that good even with my saw knowledge
- when you choose a trim, pick one that is meant to be either purposefully less or more deep than the panels - this will save you LOTS of putty and sanding time
- picking the pre-primed trim won't save you that much time, but it might be cheaper
- do two coats of primer
- use this video to learn about how to cut crown moulding
- buy one of these to measure your corner angles so you know what cuts to make
- use this chart to set your angles on the saw
- expect that things will go wrong, more than once, but just keep going... and when you get stuck..
- call me :)