Tip - too few stitches for your circular needle?

If your circular needle is a bit too long for the number of stitches you are working (this can happen once you start decreasing), pull the wire through between the stitches at the bottom of the right hand needle to shorten it. When you get to that point, repeat the process. It sounds a bit fiddly, but once you get the hang of it, it becomes automatic and is easier than switching to a set of 5 needles.