Camera shake is one of the major causes of unsharp photographs.
The best solution is the most inconvenient one - the tripod. Don't underestimate the value of a tripod, which becomes essential for close-up work.
A very useful technique becomes available with digital cameras - the ability to alter the ISO. If necessary, I increase the ISO to whatever value needed to give me the aperture and shutter speed I need. Combined with Shake Reduction technology, this makes possible sharp images where it was not possible before.
It is true that increased ISO means increased noise (grain with film) but a sharp noisy (grainy) image will be better than an unsharp smooth one any day.
Whilst normally I use ISO 200 I will not hesitate to go up to ISO 1600 if required.