Or have someone else shampoo your child's head and neck. Nits may be gray and hard to see. They are even harder to see in blond hair. Start at one spot and go row by row, or even strand by strand. Use tweezers, safety nail scissors, a nit comb, or your fingernails.
Some products come with a nit-comb.
Dip the comb in vinegar first. This will help loosen the nits. Comb the hair from the roots to the ends. Check the comb for nits after each pass. Or, divide the hair into 4 or 5 sections with hair clips.