#1: Baking Soda
This is the quick-fix instant whitener. Keep a box in your bathroom cabinet, it's magical. If you are about to go out and looking to go a shade whiter, this is the solution. Just wet your toothbrush, dip it baking soda, and give your teeth a decent scrub for a couple minutes. Rinse and smile. It's unbelievable. You can also use it more regularly by doing this daily.
#2: Hydrogen Peroxide
Hydrogen Peroxide is a fantastic little bubbly wonder. It has a plethora of uses around the home, most notably cleaning wounds, getting blood stains out of clothing (girls, take note- PMS shall not ruin your clothes.), and whitening teeth. Swish it about like mouthwash for a bit, spit it out, but then don't rinse your mouth for water for a couple minutes. If you have sensitive gums, it can be a little tingly. This is more of a progressive type of whitening, so it may take a couple weeks of doing it daily to see the results....but it works. Also, if you have any mouth sores or white bumps on your tongue, do this a couple times a day for a few days and it all gets fixed!
YAY! WHITE TEETH ARE AWESOME