I first square up and trim the quilt. I make my binding 2 1/2" wide, folded and ironed in half. When attaching binding to a quilt, you do not use a 1/4" seam. What you do is sew in 1/3 from the edge, lift presser foot. One third is in the seam allowance, one third is on the front, and 1/3 is on the back. When sewing to the corner, stop at the same distance in from edge, fold fabric diagonally up, line up the edge and fold down. Start again at the very top and sew thru all fabrics, continue sewing till the next corner. I always check the corners and sometime have to go back and take a stitch or two more, they usually come out perfect. Since I do not want to spend time hand sewing the binding, I sew my binding on the back of the quilt, turn over (I iron it), the sew the binding on the front. Some of my friends even use a fancy stitch on the front. Here is a video of exactly how I do it (minus her measurements and seam allowance). Good luck.
http://www.mccallsquilting.com/mccal...nding_to_Quilt