well, when you start something you need to go on a logical approach: in the first place you define the 2d shape of the body of the violin (use a plane, subdivide it, get the shape; a background picture is very usefull). don’t go for a perfect geometry, because you have to subsurf the mesh later on. after you get a pretty nice shape, add the subsurf modifier with 1 or 2 subdivisions (two works best for nice smooth edges). keep in mind two things: you need enough vertices on the center part of the body for the soundbox (the face of the violin is slighty curbed in a convex way) and also you need some beveling for the outer part (the edge is also bend). after playing with the shape until you get the aspect you want, duplicate the mesh, leave one on another layer, just in case you need some further adjustments later one, apply the subsurf modifier on the other mesh and start adding the f-holes (which can be done with a boolean operation).
here are some pictures of the violin i’m working on to help you understand what i’m saying:
violin1.jpg shows the mesh i worked on to get the shape: you can see that it’s really low-poly
violin2.jpg shows the mesh after the subsurf was applyied, the mesh i carved the f-holes in with the boolean tool
bubu3.jpg shows a final render of the violin body. you can see that is pretty smooth and the edges bevel up nice, as well as the sound box bend (actually you can’t really see the sound box bend, but you can see those fine shadowish parts that result from the bend)