The first step you must take is to schedule the appointment with the dermatologist and inform him what type of skin tone you have in mind. If you have pictures of the person having your desired skin tone, you can show the picture to the dermatologists. One must remember skin whitening or fairness treatment, or face whitening treatment would produce effective results, but you must not expect miracles. An individual with very dark skin cannot expect to become extremely fair and get a milky complexion.
After consulting the dermatologists, you can decide on an option based on your budget, requirement, and more importantly, your health.