Well, from my experience (and my brow is by no means light) if you pluck your brows as thin as you can from underneath, you can highlight underneath them extensively while doing eye makeup; white or pale eye makeup going on the corners of the eyes (where they meet your nose), underneath your brow ridge (to bring things forward)...basically, if it's dark on account of your heavy brow, make it pale. Also, and it seems a bit counter-intuitive, I like to use a bit of dark eye pencil on the top of my eyebrows to make them appear a bit higher. Those are my tricks, and eventually you'll discover your own' best of luck!