I prewash then iron and sometime lightly starch the fabric. After ironing the fabric I let it rest on a curtain rod or shower rod. Before I cut, I "true it up". Making sure it hangs true not at a twist. Then I square it up. If I have a large piece, I cut about a yard then. I use non skid shelving to help prevent fabric slippage. I just place a 1/2" strip at an angle between the ruler and fabric. You also want to make sure the cutting table is level and solid under your mat. I agree with the others also you may want fresh eyes to see what you are/not doing. Good luck.