So I've been looking at other nail blogs and other girls' nails, and they always seem so long and thick. (Oh god...THAT'S WHAT SHE SAID!...Couldn't help myself.) At work, I Googled a quick query of "natural nail thickener" and came across this site. One of the major things I took away from it was that nails benefit from biotin.
WTF is biotin? It's in cauliflower, and it's good for hair, nails and rhino horns alike. I am not a fan of cauliflower, and I don't feel like eating it EVERY day to strengthen my nails or my rhino horn. So...to Wikipedia! Turns out, biotin supplements are available at most pharmacies.
So consider adding that to your daily vitamin regiment.