Time how long you brush your teeth. You should in fact spend no less than two full minutes doing it. Make sure that you brush the outside, inside and tops or bottoms of every tooth. Also make sure that you brush underneath or above both of your gumlines too.
Avoid brushing your teeth with an extremely hard-bristled brush. It makes root surfaces more open and and could actually make your gums recede. You might also damage the enamel on your teeth. Any of these things can contribute to hypersensitivity, so stick with toothbrushes with soft or medium-soft bristles.
If you notice an increase in cavities, consider taking a multivitamin. Multivitamins contain many vitamins and minerals necessary for enamel production. Enamel is the outer layer that hardens your teeth and protects them. Your diet should include a variety of sources of calcium, which is the building block of healthy teeth.