Our guild stressed doing this when applying borders. Cut the borders, then mark with a pin the center of the quilt where the border will be. Mark the center of the border; match, then pin the border on. Do this on all 4 sides, doing the sides first. This has worked for me, and also pressing as you go.
Carol Doak in her book, "My first Quilt Book," gives very much the same directions.
Mariah