while my mitered corners are not perfect, I have learned a couple of tips I pass along to my beginner classes. One is to make sure you fold up at a 45 degree angle and then when folding the strip back down, check that the left hand edge is lined up perfected--if it's cattywompus it won't fold over into a good miter. also, when you are backstitching at that fold, stop about one stitch before the top edge and make sure not to backstitch up into the seam allowance, it tugs when you are folding over for the miter. I use the F. & P. method for joining the ends--just pick up any F. & P. magazine and they will show in the back technique section (was just in latest Quilty issue). Good luck!