A couple of months ago, I posted my method for getting a newborn to sleep, swaddling. This method works until the kid turns into a rolling ninja. You know that swaddling won't work anymore when you find them flipped over and unburritoed! This happens around the four month mark.
So what do we do now? My advise? Move the child away from your bed (or into their own room) and into their crib. This is the point when I begin to expect my children to sleep through the night (confirm this with your pediatrician but don't ask your babies' advice :)). Simply put the baby in their crib (baby should be sleepy but still awake), give them their pacifier (if you use one) and something to squeeze, say goodnight, and walk away. If they cry, wait ten or fifteen minutes, and then go in and touch them (don't pick them up), return their pacifier to them, give them back their lovey doll, and walk away.
If the child wakes up in the middle of the night. Go immediately and repeat this process. Don't wait fifteen minutes for them to totally wake themselves up. If they think they need to eat, don't feed them. Give them a water bottle. I've done this with all three babies, and after about two nights of water, they get the point. I know they really don't need it, but they sure like their midnight snacks. If you are nursing and baby is going through a "growth spurt" you might feed them for a night or two, but if it continues past the spurt, you should reinforce the sleeping all night expectation.
Moms and Dads...stick to your guns, and set a proper schedule. Those nights of sleep interruption do not have to last a full year!