What can i do to fix the slight tooth discoloration after getting braces off?

Whitening toothpaste: Brush your teeth with a whitening toothpaste. If after a while you are still bothered by any discoloration then you should see a dentist- they can do any number of things to remove the staining.

Depends.: White spots are due to loss of calcium in the enamel. Use a remineralizing toothpaste. Dark spots could be stain which is removed with a normal dental cleaning or a cavity which will need to be fixed or residual bonding from the brackets which a dentist can remove.

See your dentist: There are a number of reasons why a tooth can be discolored after braces. Sometimes some cement is left over after removing the braces which can get discolored. Also some foods react with the cement that was used for braces, in that case you would need microabrasion to remove the discoloration. If the lesions are deep, then you may need a bonding (white filling).