Use a shampoo and conditioner that is specifically geared towards curly hair.
Avoid using narrow toothed combs and brushes, use wide-toothed combs instead which has less of a tendency to cause breakage and frizzing.
To detangle your hair, in the shower start with your hair moist and conditioned (which will protect it from breakage), use your fingers to begin the untangling then finish with a wide toothed comb starting from the end going up finishing at the root of the hair. Then rinse your head with water and try to retain half of the conditioner in your hair. If you try to detangle your hair when it’s dry, you will cause it to frizz.
Let your hair aid dry to reduce frizzing, avoid brushing and using a towel to dry your hair. If you need to your hair to dry quickly, blot your hair with a towel, but do not rub it.
Deep condition your hair once a month or more to re-moisturize your scalp and hair.
Use a small amount of styling product with moisturizing ingredient(s) in it to keep your hair from frizzing when your hair is still slightly moist and gently style with your finger. Apply the styling one section so that it is equally distributed.
Avoid playing with your hair or touching it as much as possible, the more friction that occurs on your hair will cause it to tangle and/or frizz.