Cut your border strips. Lay them right sides together at a 45 degree angle. Using your ruler, draw a line from corner to corner as shown. This improves accuracy, especially for wide borders.
Pin in place and sew on the line.
Using the rotary cutter and ruler, cut the excess off ¼” from the seam and press open. Repeat this process adding strips until you have border lengths that extend beyond the quilt on both sides. They should be at least as wide as the cut size of the border.
For example: If your quilt is 60” across and your border is 5” then your border length should be at least 70” giving you a full 5” hangover on each side. Remember to recalculate for the side borders once the top and bottom borders are on, or you may end up shorting yourself.
Fold the border in half to find center and mark it with a pin. Do the same to find the center on the quilt. Pin the two together at this point.
Find a flat place to lay the quilt out. Continue pinning the border to the quilt working your way out from the center in each direction. Do not stretch the quilt in any way during pinning or you may end up with “lettuce leaf” borders that ripple.
Put a pin ¼” from each end of the quilt. Start stitching at the pin leaving that ¼” unsewn. Stop stitching at the pin on the other end, leaving the last ¼” unsewn.
Sew the border on the quilt with a ¼” seam allowance. It may help to sew with the border side up and the pieced quilt facing the feed dogs. This way, they can do all the work of “easing in” any excess fabric.
Repeat this process until all four borders are on the quilt. Start the next border right at the first border seam or ¼” from the end of the quilt.
Be sure not to stitch over the first border while sewing the side borders on.
Press the borders out flat and smooth out the corners.
Take the top border and turn it under to match the side border. This should be a perfect 45 degree angle; the corner should be square at this step.
Press with a steam iron to get a nice crisp flat crease.
Gently fold over the edge of the quilt just enough to get pins into where this crease was pressed; you want that angle to stay right where it is.
Sew the miter together right down the middle of that crease, backstitching when you start and stop.
Cut the excess off ¼” beyond the seam.
Press this seam open.
Turn the quilt over and press the seam from the front making sure there are no hidden puckers or loose stitches.
Repeat for all four corners