How can i repair my teeth enamel?

You won't be: Able to repair your enamel. See your dentist for repairative options.

That depends: On what type of damage you are trying to repair. If you are talking decalcifications with an intact enamel surface then you can get prescriptions from your dentist for products that contain bio-available calcium and phosphate mixed with Fluoride (mi paste, remin pro) that can repair microscopic damage to enamel. If you are talking pitted or decayed enamel then only a dentist can repair it.

Usually surgically: Most damage to enamel, fractures, chips, crazing, severe decalcification, and other damage requires a dentist to remove the damaged part of the tooth and replace it with a restorative material. Generally not a diy project. Please see a dentist for professional care.