Film Poster - Improving My Vectors

Building on yesterdays crit, today I started looking at ways to improve my vectors for the film poster idea that I'm carrying forward. I spoke to the IT Technicians about this and the way they suggested I do it was this:

Crop down the image to the area you want to focus on

and make it black and white and use the levels and curves

to try and create variation in the light and dark patches in

the hair.

 Rub out the rest of the image and the use the cutout filter

to reduce the number of colours in the hair.

Take that into Illustrator and vectorise it. It's important to

do it manually as opposed to using live trace though, as live

trace makes it just black and white, you lose the light and

dark and end up with a silhouette.

This method seems ok, but isn't really what I was after, as it didn't really show enough detail to overlap the silhouettes because there's still a lot of block colour involved. Another problem this threw is up is that you have to have good quality images to start with, which meant that I wasn't able to apply this method to all my images for a few reasons. 

1. The image on the left is too dark. I couldn't get a better image of that particular disguise, and so I would be very limited to how I could develop that image.
2. The character in the central image never has his full hair in shot unless he's stood at a distance, meaning I couldn't get a good screenshot.
3. The character in the image on the right is only ever looking down the camera in this scene, where there's some tinted glass over his head, which again limits what I could do on photoshop. 

I looked online for tutorials on how to create hair in illustrator and only ended up being dis-heartened. Most of them were on how to create vector art, which doesn't have to two colour restriction, or were very extravagant and were completely inappropriate for me to try to create given the time scale and my limited skill/knowledge of illustrator.

Clearly improving my vectors directly on the computer isn't going to improve them in any sort of way in the time scale I have available.