nice job , def not bad

one thing do not use refs like that in a chopped picture it always looks really unrealistic

and def. needs more shading underneith
best advise at the moment would be, take more time on selections , they are not consistant in shape some things should be more round in bends ..
also try to set the feather option to 0,2 that way you wont get those choppy lines (jagged edges)