Gradient Fail

I tried to do black/gray/white gradient nails today, and they turned out bad. Ugh. I'm posting a picture here so ya'll can see my fail.

I'm not even going to go into what I used because it's not worth it. You'll see some glitter on the pinky finger because I hoped that might help, but it didn't. This is my right hand (normally I take pictures of my left since I'm a righty) so sorry for the weird picture -- it's hard to use a DSLR to take pictures plus I didn't care about getting a good picture. I just wanted this off.

Any suggestions for how to do gradients in the future?