First, the quilt needs to be squared as close as possible. I always cut my binding on the bias so that I can have just a bit of "fudge factor". Personally, I think with binding on the bias you can turn it over to the back much easier and you can fiddle with the miters easier.
Before binding, lay the quilt out on the floor or a bed and see if you have any waves before you begin. What is there before will really show up after. You need to "square" the quilt after you have done the quilting.