What should you use?
You can fill your eyebrows using powder eye shadow or brow pencils or brow fillers. Filling them in gives definition to the face. Normally, the selected color should be a tad lighter than your natural hair color. For Indian skin tones, a deep brown or a soft black is good enough.
How to fill them in…
When you start filling in your brows always remember to start from the thickest part of the brow i.e. the centre. Start with less and keep building up. Keep checking in the mirror, so you don't over fill them or darken them too much. The moment you feel that the desired intensity has been achieved, stop. This differs from person to person. Use short strokes and do not forget an eyebrow brush which is usually angular with stiff bristles. In case you don't possess one, you can still achieve the same with a stiff eye shadow blending brush and even just a cotton bud!
Now, from centre follow the shape of your eyebrows towards the arch and both ends without changing the shape. In case you feel you have gone overboard filling it in, you can always dampen a cotton bud in makeup remover and gently wipe it off.
If your eyebrow hair is stubborn, fill it in and then use transparent mascara or even a dab of translucent lip balm to set it in place.