i saw on a show to start 2" from the point of the corner. angel down 1/2" to the corner point. so you will start 2" from the corner, measure down 1/2", and sew into the corner. do this on all 4 corners. the pillow will pump up a bit.
i also use a larger pillow form than the pillow itself. and I have stuffed the corners also. When I don't use a pillow form, I stuff the corners very firmly.
I can't wait to hear what every one else comes up with.