Basic lens cleaning tools are a blower, a microfiber cloth, and lens cleaning fluid (my favorite: Zeiss). Try to blast dust off the lens with the blower or canned air. Finger prints can be removed with a circular wipe of the new miracle micro fiber cloth (my favorite brand is Pentax because it is nice and thick; about $6). Persistent dirt should be removed with lens cleaning fluid, of which the safest is probably Kodak. Always drip the fluid onto the cloth and then wipe the lens; never put fluid directly onto a lens.