Once you've found a nice pair of wedges, with a smooth surfaced heel, use a sharpie to draw out your design. You can use a pattern or stencil or just freehand it! (Use tape to hold your pattern in place.)
Use ModgePodge to apply your flocking to the desired areas. Its gona be messy- just be brave and go for it! Wait until each layer is dry before adding a new one, it might take a few to look even.
Once your flocked area is dry, (and you've dusted all the lose powder away with a paintbrush) you might need to clean up your edges. Use a butter knife or scraper to score and push the flocking until you're happy with your design. (Do not cut your finger, or push at your flocking so hard you chip it all off!)
Once the flocking is done finish off your shoes with glitter. (Or not, why not use all flock!?) You're also going to use Modge to adhere this, and seal it in. You will not be sealing in the flocking, or you'll lose all your fuzziness!
Use a paint brush once all the Modge is dry to brush stray glitter from your flocked design and TA-DA! More flocked awesomeness!