Choosing a pillow for a great night’s sleep can be as complicated as picking out a bed and mattress. Fill, size and fabric will all influence your decision, but don’t underestimate the importance of your sleeping position. Side sleepers need a firmer pillow that’s as thick as the distance between the ear and outside shoulder. Back sleepers are advised to think flatter and softer to keep their head and neck in alignment. Stomach sleepers should go soft or pillow-free, though they might want to place one under the stomach and pelvis to prevent back pain.