Advice for a newbie with a marine tank

[landshark]

When I build my structures, I lay down small pieces of flat live rock or plastic as a makeshift footing for the bigger pieces. I try to use pieces that are same or slightly shorter than the height of your sand, (while laying directly on the glass bottom). This supports the first layer of your liverock at the height of your sand. This allows any sand sifting or burrowing fish or critters to easily tunnel under the rock and not disturb the supports that are holding up your display. I've never had any problems doing this and it is easy to do with sand allready in the tank.