Oh, the colors and lighting are beautiful in my opinion!
It also takes a while to get a feel for the Grab Brush; it is a fantastic Brush, but try not to make it too small (at least that was my mistake in the beginning). Also, I (like Kent also mentions) find it easier to use the Mouse, when using the Grab Brush.
Like Adrian said, Sculpting takes a lot of practice, but it is really worth the energy you put into it. And your shark is already, maybe 95% there.
