Obviously I haven't read the book, but is it supposed to be set in the 1970's skinhead era or some later revival? If in the 1970's, you've got the fashion wrong. For example, the boots in the first image are "new rocks" whereas skinheads wore Doc Martens. Where are his safety pins? Skinheads decorated themselves with these before punks did.
In the other images, the guy looks altogether too modern. The white tee-shirt is too immaculate (clean, ironed etc) and he looks too much like a model. Skins were rough looking and took pride in being scruffy. Google some images from the period. Then get your model dressed more like those images.
One other thing to remember, if this is the cover image for the ebook, is that most eink readers will transpose it to black and white, so keep the contrast strong. In image software (Gimp, or whatever) drain the colour: can you still see all the important elements clearly?
Article about Doc Martens boots: