Limit your snacks you eat a day, especially high sugar ones

Every time you eat, food gets in and around your teeth. When you eat food containing sugars or starches your teeth are exposed to these acids for 20 minutes or more. The acid attacks can break down the enamel surface of your teeth, leading to a cavity. If you must snack, brush your teeth or chew sugarless gum afterward.
Try and make sure you are eating a balanced diet also. Not getting enough minerals and vitamins can affect your oral health.