HI guys.
Sorry to jump in a bit late.
First (on the dio). I saw this in Ron's gallery last week and I thought it is great. Good composition and overall build.
Second (on the Photochopping) I think leopold did a good job in putting the background there. The boundary lines between the model pic and the background are almost OK. It is really difficult to have a clear cut or well-defined boudary lines. For you to have this, you should have a very hi-resolution pictures. With high res pics there will be more pixels defining areas and Photoshop works in pixels. It is advantageous to work originally in a very large-sized pic (meaning hi-res pics) when defining and cutting boundaries. Once you're done you can just reduce the image size. Also use dark uniform colors for your background when taking the original pictures. Or colors that are very much different from the colors of the items in your dio. This will help Photoshop differentiate from the background and the items in your dio.
Anyway, as I have said you already did a good job. I don't recommend reading the manual (he-he-he) it drove me crazy when I was starting on Photoshop. LOL.