Use bias strips, joined on the diagonal, to sew to the quilt with a 1/4" seam allowance. Sew to the corner, stopping a 1/4" from the edge. Fold the bias binding at a 45 degree angle, then fold it back on itself aligning the raw edges of the binding with the raw edges of the quilt. Continue sewing the binding to the edge of the quilt. Stop at each corner to fold the binding until all four corners are finished.
When folding the binding over to the backside of the quilt, flip the binding using your fingers to hold in place to create a mitered binding corner.