I want to ask here how they look and what could I do to improve them?
Er, it's kind of hard to tell, because you drew them in either a simple program (like MS Paint) or a better one but with a Pencil tool, and I'm going to guess you used a mouse. This would be like trying to learn to play piano with winter gloves on. Your eyes aren't going to look right if you can't make round pupils and smoother lines. I mean, you could sit there and refine them pixel by pixel, but I'd suggest using the right tools instead.
The very best thing to do would be use a real pencil, and to get the images into a computer for feedback, scan them in. If you don't have a scanner, your local library might have one, although most printers these days come with one, too. Use a pencil, and draw a lot. Practice. Learn to look at things and try to draw what you see (not what you think you see -- for example, eyes are usually lower on the head than people think, and in anime/manga they're often even lower than that). There are a lot of good drawing guides online that give you important fundamentals. Definitely get to know the human figure, because it's difficult to get everything to look right. And when things don't look right, people really pick up on it. It's essential to get a sense of how everything goes together. If you draw just eyes, you might get good at drawing eyes, but when you actually go to draw the face you may find that everything looks "wrong."
Even if you plan to do everything digitally, *everything* you practice with pencil on paper is going to help. There is no wasted effort.
If you do want to draw digitally, invest in a tablet. I mean, you *could* get away with a mouse if you had to (just like a piano player *could* actually play with gloves on), but it's difficult, constraining, and prone to error. Why jump through hoops? But, tablets cost money, so it would probably be best to stick to paper for awhile. Good software is also important; thankfully there is a good free option with GIMP. Photoshop is great, but costs money.
(except eyebrows as those seem a bit strange to me)
I'm not sure if in your drawings you meant for the lines above the eyes to be eyebrows or eyelids. The lines *are* where the eyelids should be drawn. Eyebrows will be drawn significantly above that, and it's easier to understand their shape once you've studied the shape of the face. I'd recommend looking at/drawing some real faces because anime is much less detailed. But if you understand how eyebrows look on a real person, you will quickly be able to understand how they look in anime even though they are drawn differently. They aren't just lines drawn above the eyes; they are shapes that follow the 3-dimensional structure of the face.
Hope this helps. Good luck!
Works in Progress:Vignettes
(when I'm tired of working on A Turbulent Age)A Turbulent Age
(when I'm tired of working on Vignettes)