Brush twice a day for two minutes with a fluoride toothpaste — 1,000 to 1,500 ppm for adults. Last thing at night is the brushing that matters most.
Spit, don’t rinse
Rinsing with water straight after brushing washes away the fluoride that would otherwise keep working on your enamel for hours.
Manual or electric?
Either works when used well. Oscillating-rotating electric brushes do slightly better in studies, and the built-in timer helps most people actually reach two minutes.