Summarize this article:

Hair grows about 1⁄2 inch (1.3 cm) per month, and often becomes damaged as it gets longer. If your hair is damaged or has split ends, it will likely have trouble taking curls. Getting your ends trimmed frequently will help you create your dream curls. Long layers will hold a curl better than straight-cut edges. Ask your stylist for long layers to help you create curls. Adding mousse or curling cream creates body and helps your hair hold curls. Evenly distribute a quarter-sized amount to your hair before styling it. Read the labels or ask your stylist to find out what product type best suits your hair. When you're planning to curl your hair, cut your conditioner in half. Conditioner can weigh down your hair, which can make curls drop out of it. Root boosters add volume to your hair. Spritz a small amount of the product at the roots of damp hair on days when you are planning to curl your hair.

Summary:
Trim your hair every 6-8 weeks. Get a haircut with long layers. Create texture with products. Use less conditioner. Try a root booster.