I don't press my binding - I used to, years ago, but tried it without and find my binding lies flatter and is easier to do (for me, anyway - I used to find ironing the binding in half very fiddly, but then I'm not a fan of ironing)
I tend to use one pin to pin at the start (so that I remember to leave extra for the final join) and then use one pin about 10-15 inches down as I machine on the binding, moving the pin another 10-15 inches as needed.
I machine the binding on one side, and then hand sew to finish it - I enjoy hand sewing, but do not have the time/patience to do the whole binding by hand, so this seems a good way to do it. I machine on the back and hand sew to the front, so I can see the finished quilt emerging as I sew round, which is very satisfying!!