If your hair is as dark brown as mine the best color highlights would be copper, maroon, or a chocolate color; you could try a honey blond if you want lighter colors.
As for the razor haircut...it depends if your hair is straight or not. Razor cuts work best on straight hair and if your hair is naturally curly it could cause your hair to frizzle out due to the less weight pulling it down.
Hope it helps!
Try getting a Rhianna Look. Her hair is very low maintenance.
If you want a rockerish look, maybe grow you hair medium length? get a side fringe, cut some layers into it. Maybe dye all of your hair darker? then put some higlights in it. but if you want short brown hair with highlights, maybe try a caramel/lighter colour streaked throughout your hair?