The BEST mascara I have ever tried--and I've tried a boat load, is Christian Dior-Dior Show. It's a little pricey, but what it does for your eyelashes is unbelievable.
Try L'Oreal voluminous or Maybelline volum' express. They make lashes thick and full and dark, without lengthening too much. L'oreal one has less clumpiness though.
use loreal paris double extend i love it my eyelashes are long to just get a eyelash brush and after you but it on kind of brush through them....it spreads the mascara and makes them look thick.good luck