Many ways. This is patient specific. There are many ways! depending on your smile, something as simple as whitening is a great start. The position of your teeth can affect how light is reflected off of them and make them appear darker or not as compelling. Orthodontic treatment can help you there. Another option are veneers to correct what you do not like. See your dentist, they'll be happy to help.
Dentist. The dentist has lots of new treatments to make teeth look "dazzling" talk to your dentist.
Depends on you! Today, dentistry offers more options than ever! from the simplest procedures such as whitening or gum recontouring to dental veneers, crowns, and a combination of these tool. I advise seeing a prosthodontic dental specialiss---they are the only true "cosmetic" dental experts. Their training and experience will provide you with a long lasting, functional, & beautiful result.
Dazzling Smile. Start by becoming real good at brushing and flossing twice daily, morning and evening. See a dentist to get a comprehensive examination of your mouth. Let him know what is it that you are looking for and your cost range. He will recommend the best avenue to get you to your goal. A positive mental attitude will help a lot towards your dazzling smile!