Sponging is one of the fastest and easiest way of creating amazing nail art designs. Galaxy nails are usually done through this technique. My favourite, though, would be gradient nails because the porous texture left by the sponge makes blending super duper easy.
Feel free to click on the image below to enlarge the tutorial.
I like to cut up my make up sponge into smaller bits so I'm not wasting it. I'm pretty sure that kitchen sponges would also be fine. Another great tool is the spongey eyeshadow applicator. Make sure to gently dab off any excess before dabbing the colour onto your nails. I like to dab on the tip colour first then go back and dab on a bit of the base colour if the tip is too overwhelming.
The trick is actually not to worry about being messy or too fussed about the bumps left by the sponge while you're dabbing. A layer of topcoat will fix everything down with a super smooth surface.
The end result:
Base colour: Essie Splash of Grenadine
Tip Gradient: OPI Dim Sim Plum
You have no excuse not to have gradient nails. I will take over the world, with a sponge at a time.