Until your child is about 2 to 3 years old, it's best to brush her teeth for her, until she has the level of motor coordination and attention to detail needed to properly care for her teeth on her own. Around her second or third birthday, ease your child into trying to brush her own teeth: Try brushing your child's teeth first, and then have her repeat what you did.
Not sure how to best hold your child as you brush? Sit her on your lap, facing away from you and supporting her head with your arm -- or, alternatively, rest her head in your lap. When your child is a bit older, stand behind her while brushing her teeth.
Choose a soft-bristled, child-sized toothbrush with a handle designed to fit comfortably in your child's hand. Use a pea-sized amount of a fluoride toothpaste for children age 2 or older, and be sure to have them rinse and spit after brushing to avoid swallowing too much fluoride.
Now that you're set up, it's time to brush. While performing each step, talk to your child about what you're doing, why and what the next step will be -- there shouldn't be any surprises. First, brush the inside surfaces of all teeth, angling the bristles at 45 degrees toward the gumline (the angle is important -- this is where plaque accumulates most). Brush one to two teeth at a time using a gentle, circular motion.
Next, clean the outside surfaces of all teeth. Again, be sure to angle the bristles toward the gumline, and brush each tooth with short, gentle circular motions.
Finally, brush the chewing surface of the teeth, and for added good hygiene points, don't forget to brush the surface of the tongue.
Another good way to establish good at-home oral care for the whole family is to make brushing a family habit. Brush together as a family twice a day, especially before bed, for two to three minutes each time. Lose track of time while you brush? Set a timer, upgrade to an electric toothbrush with a built-in timer, or brush along to a favorite song. Also, let every family member choose his or her own toothbrush and toothpaste -- selecting their own style of brush and flavor of paste may help to encourage toothbrushing.
Finally, one of the best ways to be sure your child is learning correct oral hygiene habits is to schedule a dental checkup. Bring your child to her dentist (or hygienist) for a professional lesson about teeth and how to care for them.