thanks, I am working on a smaller portrait right now, It looks much better than this one.

 Pretty good, you're learning about portraiture step by step. :)

I would suggest working at about %50 the size you are working now -- it will make everything much more manageable, and you will still have plenty of room for detail.

Keep up the good work!

The hair looks kind of like it's floating on top of the head, instead of following the curve of the scalp. Still, I'm not really one to give advice.

 thank you.I will rather draw a portait of my classmate because I think it will improve my skills more than it would if I just recoloured and changed some minor things on this piece

I think that you have improved. As you mentioned the skin tones could be better, and I also think that the lips are too dark. Even if you were bored with this, I think a little more work will produce good results.