It looks like the wing support struts are a little thicker than they should be. Do a Google image search for "biplane" and you'll see what I mean. The outer struts tend to be thick (although not as thick as yours) and the cross struts are usually thin (sometimes only a heavy wire).
Also the wheels appear a bit wide.
The fuselage and wing shapes look very nice as does the propeller, which is really the hardest part of a model like that.
Good job!
MD