Sure, I scratch a lot while I draw...
I do a lot of both things. I am not a great "free drawing" artist, so I use a lot of photography and related type images as models. There are many pattern books out there that are copywrite free that many people use, but I seldom use them anymore as they are not to my style most times. I also have a lot of marine life photographers that let me use their photos, as well as my own to model off of. I do trace a little, especially when it comes to human face details, and human body parts where the shape is so critical, but I try to use real people and photography as a reference and "free draw" the most of it. Of course then everything has to be modified, sometimes a lot, for inlay- piecing, etc... so everything looks a bit different in the end from the literal photographic begining when I start with models. Generally details have to be either grouped or eliminated entirely to make it look correct as an inlay.
As for ideas- I am a marine biologist and general science and nature lover at heart, but I really am starting to enjoy inlay for the challenge of just making things look as real as possible. I would have never thought I would do human faces, but to many peope they think they are some of my best works, much to my surprise.
That and of course client recommended comissions.
Craig L.