mate the tip is to turn the ISO to the lowest possible setting. if the ISO is high there will be noise in the shot. lowest ISO, long shutter and a tripod. set it all up and then use the self timer, that way you dont have to touch the camara, so the cam will be as still as it can possibly be.
if you can bracket 3 shots, one correct exposure, under, and over exposed. then see which looks best.