The following tips for helping take sharper images is from this magazine 'Digital SLR photography' a British publication,which I find gives helpfull tips to improve ones level of taking photographs,if of interest try out their website www.digitalslrphoto.com.
Taken from the above publication.
People usually get blurred photos due to slow shutter speeds. Shutter Speed > Focal Length NR. If when you use faster speeds your photos are to dark,simply choose a wider aperture [ Smaller F/* number ] or/and Higher ISO number.