Most experts recommend starting when your baby is between 4 and 6 months old. By about 4 months, babies have typically started to develop a regular sleep-wake cycle and dropped most of their night feedings. These are signs they may be ready to start sleep training. Many babies this age are also developmentally able to sleep for long stretches at night.
Fifteen minutes is all you need to perform a soothing bedtime ritual that will help your baby's mind and body prepare for sleep. Remain in his nursery or near his crib and choose the same two or three quiet, calm activities, such as reading or singing. Be sure to keep anything stimulating (tickling, TV) out of the equation. For babies over 6 months, incorporate a favorite stuffed animal or blanket into the routine.
Once you launch your plan, stick to it. Parents who've been through sleep training agree that consistency is the key. Unless you realize that your child simply isn't physically or emotionally ready and you decide to put the program on hold for a while, follow through with it for a couple of weeks. When your baby wakes you up at 2 a.m., you may be tempted to give in and hold or rock him, but if you do, your hard work will be wasted and you'll have to start over from square one.