Although the old adage says, never wake a sleeping a baby, modern-day pediatricians stress that babies should not nap for more than an hour and a half to two hours at a time during the day.
"You want the baby tired at bedtime, so you want to avoid long, drawn out naps during the day," Dr. Jacobson explains. "That's probably the most effective thing I know to signal that it's nighttime that the baby has had a day when he's been mainly awake."
Dr. Jacobson also explains that you shouldn't allow your baby to sleep through daytime feedings. "You should nurse every two hours. If you're bottle feeding with a formula, usually you should feed every three to four hours." This kind of routine ensures that your baby will not only be tired at bedtime, but he'll also be well fed and more likely to sleep through the night.