I love sharp eyebrows, sharp without looking unnaturally painted there. And a tip to make it simple but nice is to apply makeup very sharply on just the underside of the brow, but keep the top a little more diffuse.
For this I am currently using an "eyebrow liner" which I think is really good! It is like a liquid eyeliner in pencil shape that paints as straight and fine lines as an eyeliner, but the shade is more natural and adapted to the eyebrows!
You can either fill in the brows as you usually do with another product, and then finish with this to get sharper lines + hair effect in the brow. In this picture I have only used the eyebrow liner!
What I usually start with is draw a line along the entire underside of the brow, and then paint hair lines as the brow hairs grow for a natural result.
By Terry Eyebrow Liner costs SEK 240 Beauty.theyouway.se and is available in blonde and brown, and I have the brown shade.