I always square up my quilt after it is quilted. If it is a large quilt, I do it flat on my kitchen floor. I place my 2 large squares in the corners of one side and place my long rulers between them. This is to make sure that the corners are truly square and the side is perfectly vertical between them. I place my large rotary mat underneath and trim, moving the mat as needed. I work my way around the whole quilt. If it is a small quilt, I do it on my table.
I cut my binding at 2-1/4 inches and sew it to the front of my quilt. I do nice corners ( many good videos on YouTube) and join up my ends. I press the binding and turn it to the back of the quilt for hand sewing.