Since this may be a hot topic for some, let’s start with the standard disclaimer:

I am going to share another of our methods for maintaining general sanity in the form of sleep patterns. This is not a principle that must be obeyed in order not to fall into sin. This is our account of how we achieved a goal that we believe ultimately helps us get our lives in order and maintain a good attitude, something that pleases God. Your experience may be different; your parenting style may make other methods more suitable for your family; you may think that we are insensitive and hate our children (in which case, we are right and you are wrong; go read something else).
All but one of our babies have slept through the night by 7 weeks. That one was raised in very different circumstances where we were unable to apply our method and therefore saw very different results.

Here are some factors that we believe will help our children to sleep for a period of 7 hours from a very young age:

• I always nurse our babies when they wake up and consciously don’t nurse them until they fall asleep. Our babies sleep close to us, but not in our bed. I rest better this way, and the baby learns to sleep well without relying on constant snuggling or nursing; this also translates to better naps during the day, when mom can’t necessarily get to bed with baby.
• I breastfeed on demand, but I don’t use lactation as an all-purpose pacifier; I try to distinguish between a hungry baby and one that just wants attention, which is a perfectly valid request on its own. Meet your baby. He learns to recognize her different cries when he is hungry, dirty, alone, etc. and respond accordingly. The breast (well… or the bottle…) does not respond in the best way to all needs.
• We also do not rock, stroke, or “play” a baby to sleep. When the baby is clearly tired, we put him to bed; she can complain a little, but not much if we do this from the beginning. We encourage thumb sucking. You may think we’re crazy, but we think that babies who know how to settle down fall asleep much more easily and are generally happier. This is especially nice when they wake up in the middle of the night and don’t *need* Mom to go back to sleep. Many people use pacifiers for this, but if the baby loses her pacifier during the night, she often cannot fall asleep until someone finds it for her. The thumb is conveniently attached and is standard equipment with all babies.
• When babies wake up during the night, we don’t let them “cry,” but we make sure they get to a *real* cry. We don’t rush to rescue a crying baby who may fall back to sleep on his own. For a newborn, this can mean 30 seconds of actual crying. For an older baby who usually sleeps through the night, maybe 5-10 minutes for us. This is not cruel. Babies can learn early on that mommy will take care of them, but she doesn’t have to instantly obey them.
• When I nurse a baby through the night, I keep it dark and quiet, and keep it short. This is not a social engagement or play time. I don’t sleep with the baby and often stop them before they’re done. Don’t delay at 2 am Our nightly feedings are usually 10 minutes or less and baby is ready to go back to sleep. I believe this trains their systems to eat more in the morning and at night, so they are less likely to wake up at night due to actual hunger. Then, when they wake up out of habit, they fall back to sleep more easily.

Again, this is how we do it. We like to sleep through the night and we like our children to sleep in their own beds. Follow the example of her husband.

Also, consider the season in your life and your own parenting style. Some people just don’t see a problem with waking up every hour and a half with a new baby, or waking up once or twice a night with an older baby. If this suits you and your husband, keep doing it with joy.
As our helpers get older and my job becomes a bit more flexible, I don’t wait as long to pick up a crying baby at night. It’s not a big deal if I’m a little short on sleep because now I can take a nap during the day. Back when we had lots of Littles and no Bigs or Middles, a night’s sleep was essential for me to keep things together during the day.