Kalidane: you're the type I'd love to work for. For an "artist", I'm not "creative" in the least.
This is the sort of thing that makes me fear and loathe taking on art as a full time financial endeavor. Currently I tell people to tell me exactly what they want before I'll even consider doing it (just friends and family and such...wouldn't be that way with random paying clients of course), then I do up quick sketches or get some reference material online of similar things and get them to approve it (it being everything, colours, positions, frame/base/etc) before beginning anything that takes more than a couple minutes. Once I'm comfortable we're on the same page, then I get into it full bore, but not before.
Following up with work in progress pics and/or info can help too. Recently was doing a wire bug for a friend at work and she informed me of some oversights/mis-measurements on my part, which saved my butt since it was being created for her father, an entomologist. On the other hand, it can bite you in the butt too. If the client gets worried because they don't understand what you're showing them or if they don't understand which parts take the most time, often the last stages take the longest and they may expect you to finish early if you get to those last stages so early in the timeline you give them.