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.
After going through your bedtime routine, put your baby in their crib, leave the room and wait a specific amount of time (say, a minute). Then go in and reassure your baby with words like “Mommy loves you” or some kind of touch, such as a rub or pat. McGinn says it’s preferable not to pick the baby up. Garden, on the other hand, reserves this method for babies seven months and older. (In her opinion, younger babies require a parental presence so they know they haven’t been abandoned, especially if they’ve worked themselves up into a frenzy.)
"By the time your baby is 3 months old and has developed a fairly predictable 24-hour pattern, it becomes more important for you to provide increasingly consistent structure. If you do your best to establish a reasonable and consistent daily routine and keep to it as much as possible, then it is likely that your child will continue to develop good patterns. If instead you allow the times of your child's feedings, playtimes, baths, and other activities to change constantly, chances are his sleep will become irregular as well."