I have insanely short lashes too. I have two tips for long lashes:
1. Replace your mascara as soon as you notice that it's not doing as good of a job as it did when it was brand new. Dry mascara will just weigh down your lashes.
2. Wiggle your wand back and forth a couple of times at the roots, then blink while bringing the wand upward.
If you are in the market for new mascara, I love the look of Tarte's Lights, Camera, Lashes! It volumizes as well as legthens, for an overall gorgeous look.