Sorry if I am repeating what anyone else has said. It is late and I'm to tired to read everyone's.
I press with spray starch and steam
I cut down the selvage (not across) it does take more fabric, cut I have a drawer of leftover border fabrics, pulled out 2 today for a scrappy log cabin.
I measure the top and bottom( or both sides). If I running short of fabric I put on the longer sides first.
I have the quilt folded in half, and fold the border fabric in half.
Pin in center and each end, space in the middle (between pins) and pin again at least 2 or 3 depending on the length. I ALWAYS stitch with the border on top, I use a walking foot when attaching my binding.
Let us know how you make out, hopefully with all the tips you will get the results you are looking for:)