>>5373153back with a link to xanthi's tutorial in case you haven't seen it yet. it is pretty much exactly what i do. just be careful not to get carried away with doing a bunch of hairs, if you do too many they will start to just blend together and it will look like a solid mass. also don't make the base layer too dark. if you want black eyebrows, do the base layer in a charcoal grey, and use black paint for the hairs, that way you can still see the hairs and all that. basically, tl;dr "less is more"
http://jointedlove.blogspot.com/2014/09/basic-eyebrow-painting-guide.html 