The Glitter Shot.. it's all the rage these days here in Jacksonville with family photography and it can be tricky but so much fun to do.
The first thing I've found is that the key is not use glitter. Use myler confetti.. you can buy it by the huge bagful at Party City or other similar party supply stores. The peices are larger, more colorful, and lighter. It also doesn't cling to everything it touches nearly as bad as actual glitter does.
Second - count it off.. make everyone knows when to breath and when to blow. (Breath on 2, blow on 3)
Don't be stingy with the confetti either, you want a bunch and you want them to blow up not down. This is tricky and hard to do without covering your face so it's going to take practice.
And never underestimate the great stuff you'll get before and after the shot.. that last one above when Wynter is watch it fall, love it and then there is this. And the misfire below and the look afterwards.. priceless