Beverages that contain acid or carbonation are best drunk with a straw to help keep your teeth white. By using a straw you can divert the beverages past the teeth and prevent some of the staining potential. Try not to fill your mouth with beverage when drinking as this will defeat the purpose of the straw.
Buy a tooth whitening product that contains about 15% of the whitening agent. Too little of the whitening chemicals and the product will be ineffective. Too much, and your mouth may become irritated by the harshness of the chemical. Try out a mid-range product; if you tolerate it well and you aren't getting good results, then move to a higher concentration.
Peroxide may not taste great, but it is a great whitener for your teeth. Your dentist probably uses peroxide in many of their teeth whitening products. Peroxide can be so powerful that dentists can whiten your teeth in one visit. Keeping this in mind you should incorporate peroxide into your dental routine a couple of times a week.