I am cutting my first "traditional" quilt top for my 2 yr. old's bed. It's just a 9patch. The first fabric took forever to cut. Cutting strips from the yardage then marking then cutting again. Then suddenly I realized I could get more accurate, straight cuts if I used the marks on the mat as a guide (DUH!) I started by cutting a 15"x15" square from my 15" square ruler. Then I lined it up with the markings and used my 18" ruler and the markings on the mat to cut 31/2" strips and then cut those into 31/2 inch squares (cutting multiple strips at once I might ad). I did this for the second fabric. It took 1/4 of the time that it took to cut the first fabric. It was like something just clicked and I will never cut fabric the same again. I didn't mark it or anything. Don't ya just love it when those things happen?