Yet another way is to run an extra 6-8" of tippet through the eye and past the original fly then using a surgeons' knot (double overhand, or, in my case, a triple overhand) add another piece of tippet, usually the next size down to make casting easier, and attaching the dropper to that. Mind you, I am not a font of wisdom and experience, but it seems to work for me.

Ed