Keep your cutter straight against your ruler and not on an angle. Use firm consistent pressure and stand so that you are over your work. I love cutting but I can't cut properly sitting down or if the table is too high. Get an experienced quilter to watch you and offer some suggestions as it may not be obvious to you exactly what is the problem. Also realize that cutting is not easy for a lot of quilters. When we have hands on at guild evenings, cutting is the least preferred job. It will get better with practice. Don't try to cut when you are tired or the light is poor. Stick on ruler guards are available if you are worried about cutting yourself. Also make sure to use Invisigrip or those little plastic grips on your rulers to avoid slips and slides. Good luck with this.