This is hardly a tutorial, but I'll walk you through my steps. I've seen real tutorials on a couple of other blogs, but I kind of just worked with what I had and went with it. You need Mod-Podge, glitter of your choice (I found this jumbo container at Walmart for $2 and used a tiny fraction of it), a paintbrush, paper cup, and plain-jane shoes.
I used canvas tennies- also from Wal-mart- for my daughter.
Inspired by these pumps from Modcloth, I decided to make a hybrid pair for myself.
I traced an outline of the area I wanted to fill with glitter, then poured ModPodge in a cup and mixed glitter in. I carefully painted the areas in with my glitter glue, and then sprinkled glitter on the wet glue to get a heavier coverage. [With my daughter's shoes, I tried just painting layer upon layer to get the coverage, and they ended up peeling :(] After sprinkling the glitter on, cover with a second layer of glitter glue and let dry thoroughly. And then have your husband/boyfriend/significant other take you out on the town in your too cute shoes! :)