Use a delay timer or remote. Believe it or not, just having your shaky hands on the camera can introduce a little blurriness into the shot. Set your camera to a short (1 or 2 second) delay, using the self-timer setting, so that you can remove your hands completely after pressing the shutter button.
Connect to a laptop or live monitor. Checking your shots at full size will help you correct issues early, before they become a problem. Use a camera cable, or take a few shots and then pop the memory card into your computer.