This is what you will need:
-glitter polish or another color
-sponge applicator (like the cheap-o things you get with eye shadows & never use)
-topcoat (I guess this is optional, but it will help your mani to last longer & will smooth it out)
-remover pen for cleanup
Step 1: Prep your nails, use your basecoat, etc. Let dry completely.
Step 2: Paint your nails in your base color. I used Sinful Colors Open Seas ($1.99). Make sure you achieve the desired opacity in as few coats as possible. I used 2 coats. Let dry completely.
Step 3: Get your sponge applicator. (I got mine in this kit for $1.99 for the sole purpose of destroying it with polish) Unscrew the lid of your layering polish and scrape the polish off the brush onto your applicator. My layering polish was Sinful Colors Nail Junkie ($1.99).
Step 4: Lightly dab polish onto your nail (at the tip, the left or right corner, one side, or your nail bed). As you dab polish concentrate on one part of the nail, I did the tip, and lightly fade it out before getting more polish.
Step 5: Wait between layers for polish to dry or it will become tacky and get indents in it.
Step 6: Continue adding layers until the desired darkness/concentration of layering polish is achieved. Do not forget to "fade" while using your sponge applicator.
*Some people swear by sponging a thin layer on 3/4 of the nail, wait for it to dry. Sponge polish on 1/2 the nail, wait for it to dry. Sponge on last 1/4. See illustration below*
Step 7: Finish with your favorite topcoat. This not only helps your manicure to last longer but it also tends to mask any minor flaws in your sponging.
Here is the illustration I created on how to sponge. Keep in mind that you can create a gradient by using polishes of slightly different colors, just like in the picture.
Let me know what other tutorials you would like to see. I can always give a manicure a shot, even if it doesn't turn out perfectly;)