How thick should eyebrows be?

It really depends on your face. Try to stay with the natural shape of your eyebrow. Put a pencil against your nose going straight up, pluck the hairs on the outside of the pencil. Then lay the pencil at an agle against your nose to get the hairs on the other side. Just remember, you can always make your brows smaller. You don't want to go tweezer-happy!!