The finished design is shown on the ring finger throughout the tutorial.
The first step is to paint all your nails with one or two coats of white. Don't worry if it's a little streaky or if you can see brush strokes like you can here because we'll be covering this up with sponging. I've used one coat of Sinful Colors "Snow Me White" here.
The next step is to sponge on your gradient. Paint a stripe of yellow and blue polish next to each other on your make up sponge. It's a good idea to have them slightly overlap. Then press the sponge directly onto the nail, and tap it on the nail moving up and down along the length of the nail to get the best gradation of colors. I've used Orly "Hook Up" for my yellow, and China Glaze "Frost Bite" for the blue. I stopped at one application of the gradient because I wanted a more pastel look, but you can sponge over it again to get darker more vibrant color.
Lastly, add a smaller light green dot in the centers of the dark green dots. I've used Revlon "Beach" here.
Just top coat and you're done!