I had read from that autobiography book called ‘I am Ozzy’, that Ozzy Osbourne shaved off his guest’s eyebrows and checked their reactions in the morning.
You wake up in the morning and what you see in the mirror is weird, something seems missing. You make very strong facial expressions on the mirror, you don’t understand why you look emotionless. Da-daa! No eyebrows!
Eyebrows play a big role to express emotions, together with wrinkles above them.
I divided those eyebrows into some possible groups:
1) Thickness: Thin, medium, thick
2) Lenght: Short, medium, long
3) Distance between each other: Close brows, medium, short brows
4) Shape: Upward, straight, S shape, soft angle arch, steep (hard) arch, round (curved)
These are all of the facts will help you while drawing.
I see people drawing eyebrows like drawing an outline and filling inside with a flat black or fill inside with many short and shorter lines. I don’t find it as and effective way of drawing eyebrows. First of all, they look so unnatural and that outline is slightly seen.
That is my eyebrow study, probably year 2015 something, must be february.

From thin to thick; where eyebrow starts, where it ends; the distance between the head and tail on a horizonal level etc.
What about the shapes; possibly the most helpful part of the tutorial:
While drawing those eyebrows I didn’t draw any contours to fill and that is what I suggest you. You may not find a good shape or the shape you want at first, but keep repeating, delete and repeat and you will surely find it.
Or another way is that you may use a light pencil at first, then when you’re sure about the shape, strenghten those lines with a darker pencil.
Now let’s see those shapes in bigger versions:
The first one is upward. See the orange circles which indicate where eyebrow starts and ends; the tail is higher and there is no curve in the eyebrow.
The second one is straight; what the red guideline shows is that the head and tail are almost in the same level. So much like upward eyebrow as the shape, but this time on the horizonal line.
‘S’ shape eyebrow exists, yes! I didn’t see before or maybe just didn’t pay attention.
Besides, soft angle arch is easier to detect, or is more common. Tail of the eyebrow has a slight ‘up’, then ‘down’.
Steep or hard angled arch is stronger version about that up and down.
Round eyebrows have these head and tail pretty much at the same level, there is a curve up in the middle which is quite soft.
Short, long, close brows and more:
Another thing to point out is that orange two-sided arrows which indicate the distance between the eye and the brows, can be another helpful fact during drawing.
One more thing that I will mention is about those orange guidelines above. Those lines are about ideal eyebrow lenght and curve point; the first one (from left to right in order) is about at what point the arch should start; second one is where your head of eyebrow should be and the third one is where the tail should end. Eyebrow artists also tell that your face shape is important for your best brow shape but that is not our point. Those guidelines are helpful when you have a referance photo; then you can say “Hey! that tail is real long.” or “Head part of the brow is not in the same vertical line of the edge of the nose; eyebrows are quite away from each other.” etc.
Some other eyebrows:

Frida from ABBA, thin eyebrows from those years.
And Gigi Hadid.
I’m planning to draw more eyebrows in the title of ‘facial expressions’ and examine emotions there, in further posts.
A makeup artist friend made me realize that my eyebrows are not symmetrical, I left them the way they are, I kinda like it.