I would also recomend that you check what the other photographers offer, like backgrounds, type of lighting, etc. Here in Guatemala most of the photographers take generic photos, with no option to get the best posibble portrait, they just say sit this or that way "look at the birdy" hehe and that's it, if you are going to give the option for your eye to find the best possible way for a person to apear in a photo, you could charge more than the other photographers.