A quick summary:
1. whitening toothpastes
2. Whitening mouthwash
3. White strips 
4. In office or take-home bleaching
5. Red lipstick 
(no really)
Read on for details!
1. Whitening toothpastes: Typically toothpastes have abrasives in them that can help to remove some superficial staining. Used too frequently and they can actually wear away your enamel
2. Whitening mouthwash: Virtually does nothing as the product isn’t in your mouth long enough to actually whiten teeth
3. Whitening strips: Strips with either carbamide peroxide or hydrogen peroxide that sit on your teeth for a period of time. These are effective for mild to moderate stains. The strength of these are mild so no drastic difference will be noted.
4. In office whitening or take home whitening: A high strength gel to provide a more drastic whitening effect
Note: I always recommend starting with white strips because:
a) they are cheaper and you may get your desired effect for way less money!
b) If you experience severe tooth sensitivity with strips, chances are in-office whitening may be unbearable for you
to minimize sensitivity before or during whitening, use a desensitizing toothpaste 2 weeks prior to whitening and for 2 weeks after
My favourite sensitize toothpaste brands are Sensodyne or X-Pur Remin
And for a instant whiter smile bust out that red lipstick! The contrast makes your teeth appear whiter!
