Take note of how the lines on the ruler line up with the edge of the fabric. On the Omni there is a blue line with yellow on each side of it. Try to place the ruler the same way each time. Cut with the rotary cutter short distances and carefully move the hand holding the ruler. If you try to over reach the ruler will slide. It can also help to have the thumb and 2 fingers on the ruler and the other 2 fingers on the mat to help stabilize it. It takes practice and patience. Good Luck.