Sometimes new students of mine have the same problem. I show them that you do NOT have to push hard. Let the rotary cutter do all the work. Make sure you are standing above your fabric slightly to the side of your cut. Your blade must be sharp also. Have the fold closest to your waist and do not press your blade against the ruler. The ruler is your guide, not your wall. Beginners should only cut through 2 layers of fabric until you get the feel for it. Take it slow and it will become easier for you.