One tip not mentioned yet, but is VERY important is this. When using the rotary cutter and the ruler, even non slip, spider your fingers over the ruler with one finger ON THE BOARD to keep it from slipping. Move this hand up the ruler very carefully,stop the cutter, slowly changing your hand position on the ruler at least 4 times as your cutter reaches your hand position.... even up to the last cut as that is often where the ruler can slip if not held in place. Make this a habit and you will be fine.