People who do not want to have frizzy curls in their hair should never brush their hair when it is dry, should use a conditioner that contains protein and should avoid over-processing their hair. Curly hair can also become more frizzy when heat tools are used often.
Hair is made up of many different parts, but the outside of the hair is made up of what look like roofing shingles. These "shingles" can lift and cause the hair to become frizzy. Brushing the hair when it is dry or allowing the hair to rest in humid climates for long periods of time can cause the "shingles" on the hair to lift up. Hair that is damaged is more prone to heat than hair that has been well taken care of.
A protein conditioner should be used to help weigh down the "shingles" on the hair. The protein will act on the hair and will allow it to become smoother and shinier, leaving more room for the curls to look curly instead of frizzy. Over-processing of the hair by dying or using chemicals can cause it to become damaged, which will make it frizzier. Heat should be used sparingly on curly hair to prevent frizz-causing damage to the curls.