in search of depth

in search of depth.. learning about light and shadows. How do I give the impression od depth in here? I'm not quit sure, but working with grey to find out. Plus ofcourse there's lots to finalize here too. But am I getting there?

I would love to get a lesson from somebody who knows. Let them dowload this image and fix one corner, then reupload it, so I can see what I need to do. I miss Konahins, it seems he closed his DA account. He's still on the net though. He's da true master, for sure

ETA: BREAKTHROUGH!! Check out my latest piece 'August Heirloom" where I finally GOT it! I'm SO excited! [link] Thank you to jswis for helpful comment direecting me to tutorials!