After several attempts, I find that "ombre nails" has got to be the easiest to do...well, at least among the other designs that I've tried.
So here's another one:
Nail polishes used:
Orly (Frosted White - used as base), Orly (Gold), China Glaze (Purple)
China Glaze (primer), Revlon (fast dry top coat)
Thanks Mom for letting me use her Shiseido makeup sponge! Sorry that you just had to throw it away after.