some people like to stack there live rock to make shelves. however other like myself like to make caves and holes for fish to swim. this also helps for flow to get behind the rocks and stir things up some.
Heres an old pic of mine: https://forums.saltwaterfish.com/t/289677/55gals-lets-see-some-pics
The coral stock/locations are different, but the rock is pretty much the same.
I think you're going to learn that 55s are tricky to aquascape because they're so tall and narrow.
-Justin
This is what i have in my (new) tank so far, i still want to add quite a bit more lr. but it cost so much $$, but it might still give you a few ideas. btw this is a 55 gal, and good luck to you.