A quilt top that starts with square cut patches and strips will sew better and lay better once pieced. By knowing the basics of using your rotary cutter and ruler you can have accurately cut patches and strips for your quilts. Also, part of knowing how to use these tools involves safely using them.
A few years ago one of my quilting friends was not holding onto her cutting ruler in the best place and the rotary cutter slipped and cut off the side of her index finger. A trip to emergency, stitches, and her hand in a big bandage is how her day turned out. The injury took many weeks to heal enough so that she could resume her quilting along with other activities.
The video below from The Quilt Show will illustrate how to safely use your cutting tools and how to make accurate cuts. Remember, every time you pick up the rotary cutter, think about safety first and the best practices to protect yourself from injury.