You can find white nail polish at any dollar store. I got mine from Dollar Tree (L.A. Colors). Using the white nailpolish, go over the white part of your nail, making a smooth line. It helps not to use too much. Clean up any blemishes with the bobby pin/toothpick/ etc.
Wait for it to dry. Once dry, go over the entire nail with clear nailpolish. I found that this brings out the pink in my nail.
I used Sally Hanson's Hardener. It works really well, but it is more expensive than just dollar polish.
**Also, i'm not sure but I believe you can buy the Hardener tinted pink.
Lastly, wait for it to dry and clean up any nailpolish that got on your skin. Taking a shower helps remove this.