While brushing for two minutes, twice a day, in almost any manner that cleans your teeth, is absolutely better than nothing, there are actually better methods to brush. Here are a few tips from Dr. Amble and Dr. Cashman:

1. Brush twice a day, after meals and/or before bed.
2. Use a soft bristled brush and a cavity preventing, fluoride toothpaste.
3. Brush your teeth with a motion following the spaces between your teeth, up and down. Don’t scrub back and forth as this action can erode the gum and even harm the enamel, eventually.
4. In general, avoid constant use of whitening and tartar control toothpastes.
5. If possible, the best choice of brush is a high quality mechanical toothbrush.
6. Daily flossing and use of a good quality mouth wash can also help prevent cavities from forming between teeth, keep bacteria under control and help keep your gums healthy.

Here’s an interesting article that talks about some of these issues.

Improper brushing leads to sensitive teeth and possibly gum and tooth enamel loss.