I just read the tutorial and wish to add a p.s. to my earlier post. I almost always have several yards of fabric to square up and trim so I lay it out lengthwise on an 6' long cutting mat. Once I get an entire 6' length lined up exactly straight, I put plastic buckets of smooth deco. rocks as weights in strategic spots to keep the fabric in place. This way I can cut long strips (for borders or binding or whatever) lengthwise, once I get the selvedge cut off. I never double fold ... I've learned that a single fold in the middle of the fabric is all I can accurately manage. Also, my rotary cutter does much better with only 2 layers of fabric to cut through.