Here are the methods which can efficiently clean your teeth as part of your dental care:

 - **Brush your teeth with toothpaste** at least for two minutes including outer/inner teeth  surface and against the gumline (sweep or roll the brush away from the gumline).
 - **Use dental floss** after brushing to remove plaque between teeth and under the gum line, where ordinary toothbrushes can't reach.
 - **Use mouthwash liquid** which kills 99.9% of bacteria and provides 24h protection against plaque (such as Listerine). Also use it after finish eating.
 - You may add **activated charcoal powder** onto your toothpaste. It absorbs toxins, a wide variety of drugs, chemicals and other impurities.
 - After your last teeth brushing, **avoid eating and drink only plain water** (maintaining the right pH and °C in the mouth can prevent a dental plaque, which can help saliva to naturally neutralize the acids produced by the bacteria and remineralize the tooth surface).
 - You may use **Plaque Disclosing gel** or **Disclosing tablets** which can dramatically highlights harmful bacterial plaque on tooth surfaces and shows the areas where more brushing and flossing are required. See: [Detection of plaque build up][1].

For a better whitening, add a baking soda. According to [Wikipedia][2], toothpaste containing sodium bicarbonate has in several studies shown to have a better whitening and plaque removal effect than toothpastes without it. If your whitening toothpaste isn't working, try leaving it on your teeth for a couple of minutes before you rinst it off.

To answer your other question about the most efficient time, it's recommended to brush your teeth at least 1h after eating or drinking acidic foods/drinks to prevent chance of enamel erosion and dental erosion. See: [Really? Never Brush Your Teeth Immediately After a Meal][3]


  [1]: https://en.wikipedia.org/wiki/Dental_plaque#Detection_of_plaque_build_up
  [2]: http://en.wikipedia.org/wiki/Sodium_bicarbonate#Personal_hygiene
  [3]: http://well.blogs.nytimes.com/2012/05/21/really-never-brush-your-teeth-immediately-after-a-meal/