Hi,
The colour in this image is peculiar, I'm not sure if it's too saturated but it is very artificial.
The quality / clarity of the image is not good; there is a lot of noise and coloured grain throughout but I'd imagine this is more reflective of the camera itself rather than your abilities however.
The position of her head is wrong, the consequential shadows are unflattering and the shape of her face looks unusual, almost like it is slanted to our right.
On a side note, and I'm sure you didn't mean it as such, a head shot would not be ready - set - click. Formal head shots are usually studio based with very specific lighting arrangements. This image is striking me as much more of an opportunistic shot.
Steve