Tips for Better Backing
Use extra blocks from your top for the back.
Piece leftover fabrics from the front of your quilt to make a backing.
A backing is a great place to showcase larger prints and those you don't want to cut into smaller pieces.
Choose busy prints if you don't want your machine quilting to show.
Working with width of fabric pieces can be challenging, but a serger makes quick work of this task! Since you want to remove the selvage edges before sewing, serging the seam cuts off the selvage and finishes the seam in one simple step. Bonus the seam lays flat and is really secure due to the serger stitches.
A couple more things to keep in mind: your backing should be at least 4" larger than your quilt top on all sides. If you plan to quilt your quilt on a longarm, piece your quilt backing with the seam horizontally to allow the seam to lay parallel to the rollers for easier loading and smoother backing.When seaming, keep in mind that you usually fold a quilt in half, it's best not to put a seam in that spot as it will weaken the fabric over time as you fold it in that spot.