You will often find instructions that say you should "bind off in pattern." Sometimes knitting pattern stitches will suggest you bind off in pattern as well.
All this means is that you work your bind offs in the same manner that you would work the row if you were not binding off. For instance, binding off in pattern in stockinette stitch would mean knitting all stitches on the right side and purling all stitches on the wrong side.
In a more complex pattern you may have to switch between knits and purls as you bind off. This makes the bind off edge look more a part of the finished project than would binding off in the normal straight knitting manner.