Mascara is one of the top products I recommend for every makeup routine. It can open up the eyes with just enough definition to hide the fact that I-got-5-hours-of-sleep-last-night. Mascara has super powers!
There are 2 main factors to consider when shopping around to find your favorite: the formula and the wand. Both carry equal weight in determining which one will work best for your lashes.
Go take a look in the mirror then come back to find your best combo.
Long and Thin - grab a thickening/volumizing mascara with a large, full brush and densely-packed bristles. Add extra fullness at the base of your lashes by wiggling the brush back and forth then coating all the way to the tips.
Long and Thick - a comb-shaped wand will help to separate and define full lashes. Use a curler and/or a curved brush for straight lashes to help open up the eye.
Short and Thick - look for a lengthening mascara with a long, comb-like brush. Lengthening formulas have fibers that "build" on themselves to make lashes appear long. Be sparing applying at the base of your lashes. Then apply a second coat focusing on the tips.
Short and Thin - find a lengthening formula with a stubby wand that packs a lot of bristles. Wiggle the wand back and forth at the base of your lashes to add fullness. Then apply a second coat focusing on the whole lash.
A few more tips...
For a Natural Lash Look, find a formula with a rubber wand and moderately spaced bristles. They hold less product and will not focus on adding length or volume.
Bottom Lashes - Yea or Nay? I think it's always a good idea to help define eyes without closing them in. The one exception would be for mature eyes that need a lifting effect by only applying mascara to top lashes.
If you have Super Straight Lashes (like me!) a curved brush and lash curler can help. I heat up my lash curler first under warm running water or with my hair dryer. A warm curl holds better than a cold one. (ALWAYS touch it with your fingers first to make sure you don't burn your eyelids!) Then I follow up with a curved brush mascara. It helps my lashes hold the curl better than a straight brush.
Lash Primer - Primers are designed to create a base for mascara to add drama and keep it from smudging.
Now, go grab a couple different formulas to get an idea of what works best for your lashes and the look you want. Total Beauty has a short quiz that gives you 2-3 recommendations to start with. I've also been testing out several mascara formulas so stay tuned for part 1 of the Great Mascara Review. Should help narrow it down a bit!
What's your magic combo?