We seem to be the most critical of ourselves when something important comes up. When booking a session, the first thing I hear tends to be about weight ("I will get photos when I lose a little weight"), but second is something about their smile. No words need to be spoken, I can see it in the body language. I can't guarantee you a 10 shade difference, or straighter teeth, but as a former dental hygienist I can help you understand how to achieve whiter teeth.
For now we will focus on the 3 ways you can get INSTANT gratification with whitening your teeth.
Over the counter (OTC) whitening strips - Starting with OTC whitening strips is where I always started my patients. It is the same product as in-office whitening, but at a lower concentration. Most people will get the results they are looking for within 10 days of using the strips alone, if not then speak with your dentist about custom trays!
Custom Whitening Trays - Custom trays are made in a dental office specifically for your teeth. It is a one time cost for the tray, but you will need to replace the whitening solution. This solution is a little stronger than what is in the OTC strips, and has to be placed in the trays. In most occasions, you will see improved whiteness within 10 days. If you have sensitive teeth, brush with a sensitive toothpaste 2-4 weeks PRIOR to whitening.
In-Office Teeth Whitening - This whitening procedure is the best for true instant gratification, but is the most expensive. This method requires a visit to your dental office where they place the strongest concentration of whitening agent on your teeth in intervals until you get the the desired effect. You will achieve whiter teeth in a matter of a couple hours that will knock your socks off, but that effect lessens over the next few days to a reasonable level of whiteness.
Bonus:
Homeopathic - I do not guarantee these will work, but they are things you will find easily on the internet. I have seen both of these options work for patients, but I do not typically recommend doing them regularly due to the abrasiveness. It can cause trauma to your soft tissue (aka: gums) or create extremely sensitive teeth if you do this on a regular basis. I would try this maybe 2x a month AT MOST!! That is your warning. Charcoal paste - You can buy pre-made by nearly any major brand paste, both natural and not. It uses charcoal particles to make the paste more abrasive and "better" at removing stain.
Baking soda with water or Peroxide - This is probably the most common homeopathic version of whitening I hear. I have never tried I (mostly because I am lazy) but by mixing one tablespoon of baking soda and two tablespoons of hydrogen peroxide you'll end up with a paste. I love before and after photos, so don't hesitate to send me your results!