Try not to use the smallest aperture in your lens (f/22, f/32) to avoid diffraction - a sharpness killer.
Hyperfocal Distance focusing at work. Nikon D2X with 12-24mm f/4G AF-S Nikkor
The Near Focus Limit is at my feet in this sunrise at the Badlands, South Dakota. 5th ANPAT
Depth of Field (DOF) and Hyperfocal Distance Calculator