Brush and floss regularly to reduce or prevent stains.
Avoid the consumption of or exposure to products that stain your teeth. If you do choose to consume beverages that stain, consider using a straw so that the liquid bypasses your front teeth .
Use an electric toothbrush (electric toothbrushes can remove 98.2 percent of plaque).
Use a mouthwash with an antibacterial action to help dissolve plaque.
Get regular dental cleanings, which remove many food and tobacco stains. No amount of cleaning will remove the severe staining left by tetracycline or systemic disease because these pigments lie inside the tooth, you'll have to take more aggressive measures against these.
Follow good oral hygiene practices. Brush your teeth at least twice daily and floss at least once daily to remove plaque. Use a whitening toothpaste (once or twice a week only) to remove surface stains and prevent yellowing. Use a regular toothpaste the rest of the time.
Consider touch-up treatments. Depending on the whitening method used, you may need a touch-up every 6 months or after a year or two. If you smoke or drink lots of stain-causing beverages, you may need a touch up more often.

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