Gamasutra.com has a lot of job titles and postings you can look at. Among those that seem to match what you're looking for are 3D artist, concept artist, rigger, animator, etc.
Drawing is a fast way to communicate and tweak your ideas before going for the long hack at 3D. I'd recommend taking observational drawing classes, figure drawing, and then trying to apply what you learn to draw things from your head. Also, sculpting would help a lot for 3D modeling.