Well you have conquered probably the hardest part of a portrait for most people; actually making it look like the person you are drawing. This is quiet obviously Angelina without even looking at the name which is fantastic. On that note it is obviously drawn from a reference photograph, unless you have some great contacts, which makes it hard to critique where things look wrong in a drawing like this.
The main qualm I have is with the shading on the eye on the right (her left). The depth of the shading and the shape of it just doesn't seem to fit the rest of the picture especially when there is a harsh change with no real graduation of shading. It has the unfortunate effect of making it look like Brad has taken a swing at her. The problem is that might be present in the image and there is perfectly drawn but it just seems odd here.
The right hand side of the shading is fine it is around the nose and eyebrow where it just seems.....odd (probably the best word to use).
The only other niggle I have is the shading on the left cheek (her right) as it seems very blotchy when compared to the rest of the shading which is nicely graded and placed. I don't know what you are using for blending here but it seems that whatever it is has picked up a lot of graphite in one place and laid it down deeper in certain places rather than evenly across. This can be solved in future by using a continual even pressure on any blending stump you use (as long as the graphite is also laid down evenly)
The hair which your worried about looks great and I would not worry about that at all in this picture. It is helped by fact she is a brunette which is far easier to draw. I can understand your reticence as I have trouble with hair especially if the subject has blonde hair. However here it is brilliantly done.
This is a fantastic piece of work and you should be incredibly proud of what you have achieved, as I say the above comments are minor details when you look closely but as a whole it is simply beautiful.
Keep up the good work and I look forward to seeing more of your pieces. Happy to help further if you wish.
P.S: the mark down on originality is simply because it is a subject a lot of people choose though thankfully not to a Hugh Laurie as House level - seriously if i see anymore of him in the same damn pose I might go insane.
thanks very much for taking the time to write a critique on my drawing. I really appreciate comments and advice. i agree with what you said about originality, i just wanted to draw a female for a change and angelina jolie has a beautiful and very distinctive face so thought this would be a good place to start. thanks again.