I decide on what quilting design I plan to use and what colour thread. With a black and white pieced quilt I need to decide will I quilt with white, black, variegated on clear thread? How will each of those choices look on the back? If I use the clear thread on the top, I can use a bobbin thread that matches any backing fabric and a coordinating binding fabric. If I choose a coloured thread, I try to match it fairly closely to my backing fabric so any boo boos are hidden. A patterned back also helps me hide mistakes. If you are a proficient machine quilter and want your awesome quilting designs to show, pick a solid back.