I think I did a tutorial like this a couple of years ago, but I've learned a lot since then. There are no correct way to paint edges, but there are some DON'TS.   What you shouldn't do 1. Burnish edges with Tokonole or similar agents before painting. You can dry burnish before paint but you have to sand before applying paint. 2. Make too large bevels on really tight folds (Your paint will stretch until it cracks) 3. Paint a new layer on a surface that's not flat (Except