I also like to create a lot of different nooks and crannies. I like to make caves that fish can swim in. Also, be sure to lay the rock on the glass and have the rockscape stable before you put the sand around it. If it's stable without the sand, then it will be even more stable with the sand. Plus, if you have a fish that burrows, it won't topple your rock from removing the sand around the rock.
Try to have a few rocks touching the sand as possible. In my tank there are only 4 rocks in the sand. Everything else is balanced on top of those 4 rocks creating caves and overhangs. Be sure to use some 2-part expoxy to secure your rocks to eachother.
I like to use a bit less rock than most people as well. In my 33g I have about 28 lbs of rock, and I definately don't want any more.
Once you start adding corals you'll probably redo your aquascape to make room for more corals!
