If you've been paying attention to runway fashion, chances are you've noticed the increasing size of many models' eyebrows. Since eyebrows serve to define your eyes, growing them out doesn't seem like a bad idea, as long as you don't let them turn into unruly caterpillars.
Overly thin brows can make you look older, which is why you may want to consider putting down the tweezers for a while and letting yours grow back to their natural thickness. It's fine to pluck the occasional stray, but don't touch any hairs that are growing more or less where your eyebrows are supposed to be.
While you're growing them out, use something like Paula Dorf – 2 + 1 for Brows to fill in sparser areas. It comes with two colors and a light wax, so you can mix up the perfect shade that will last all day.
Once your brows are grown out, use a Colorescience – Eyebrow Stencil to help you find the perfect shape. You may want to keep your brows a little thicker than what the stencil suggests – just use the guide to help you figure out how long they're supposed to be and where the best arch is.