Smooth (jogless) Bind Off in the Round
If you bind off (cast off) in the round, usually you end up with a bump at the last cast-off stitch. Here's a way to minimize the transition and have a smoother joint. 
Bind (cast) off stitches using your preferred method until you have 1 stitch left on the right-hand needle.
1. Insert the right-hand needle into the 1st cast-off stitch, picking up both of the top loops.
2. Yarn around needle
3. Pull yarn through all loops on needle.
4. Cut yarn and weave in end.