Ideal oral hygiene! Floss daily (by far the most important thing you can do, ); brush carefully, watch your intake and frequency of sugars. An unacceptable alternative would be full mouth extractions. No teeth ..... No decay!
Diet and oral hygien. Cleaning you teeth with good brushing and flossing is essential. You need to have a diet low in sugar. Drink water and avoid soda, energy drinks. Flavored ice teas, even diet drinks are bad for teeth. Using xylitol mints or gum after eating will help to eliminate the decay causing bacteria. And have your decayed teeth treated!
See a dentist. Get the decay treated, get oral hygiene instructions and a cleaning. See your dentist on a regular basis. You are fighting a losing battle without professional care.