If you haven't already, you should draw it in 3D (or at least visualize it in 3d). It will help you find any conflicts (for example, stair head heights).

The first thing that popped into my head though was to check the mechanicals, especially plumbing. Make sure vents and traps aren't in the middle of the living room. Make sure you run the plans by all of your subs so they can point out any code or installation issues.