Frizz and Damaged Hair

You have to figure out how you damaged it and make sure not to do that anymore, then take better care of it until it grows out healthy.  Things that damage hair are heat, chemicals from dye or straightening, and rough handling (towel drying to roughly such that you make knots in it, then ripping a brush through it tearing it when you pull the knots out are things to avoid).  Products with too much silicone in them should also be clarified off with a "clarifying" shampoo every couple of months, or they can build up on the hair and break hair off when the coat breaks after many months.

If you didn't do anything to damage it, and its just frizzy naturally (sometimes naturally curly hair will do this if mishandled), you may need to just modify your routine.  Such as only combing it with a wide toothed comb when wet, then not again when dry, or using a drop or two of oil to bring out the curl and shine and reduce frizz.