No matter how many people you ask about the age at which a baby will sleep through the night, you will have as many answers. There are things to do that may help the little one to sleep better, but there is no magic age that the baby will reach that sleeping through the night will happen on cue.
One thing to evaluate if you are having a problem with night waking is the baby's nap schedule. (Of course infants will be waking in the night, these suggestions are for older babies, perhaps in the 5 or 6 month age range or even older.) You may want to try to see if one less nap during the day, if the baby is having more than one, will help with the night sleeping schedule.
Newborns will not sleep through the night and should never be expected to do so. They may sleep more than 15 hours each day and every bit of rest is needed. They need to be fed every few hours and yes, this includes the hours during the night as well. You may want to try to keep the baby in an area of the house where there is activity and noise throughout the day, though, so that he or she will be able to eventually realize that there is a day and night and that nighttime is for quiet time.
Another way to make sure the baby learns that nighttime is different than daytime is to be sure to keep interaction during the night to a minimum. If you get up to feed the baby, get the feeding and burping done and then put her back down. The same for changing diapers in the night applies. Make it fast, don't do a lot of talking and don't have the lights bright. Use a soft night light if possible so that there is not unneeded stimulation happening.
A warm bath may tend to help an older infant sleep better. Maybe he will enjoy being rocked to sleep or hearing your soft voice reading or telling a bedtime story. All of these things will be a good solid base for a nighttime routine that will most likely last for many years.
At some point when the baby is older, you will need to decide how you will be handling crying at bedtime. Read up on the matter, and be sure to read both sides. Speak with the baby's doctor for advice or ask the opinions of other parents.
There are two very different mindsets on the matter. Half of the people you will speak to will say that going in every time a baby cries is a very bad habit to get into and will "spoil" the baby. The other side is that a baby needs the security of knowing you will be there when needed. Gather all the facts and then you will need to decide which side of the argument you wish to adhere to. (Again, remember this decision is for babies at least 6 months old and a younger baby should not be allowed to "cry it out" like some experts on that side of the argument suggest for older infants.)
Make sure the nursery is kept at a comfortable temperature and isn't near a noisy part of the house. The room should be dark but if you use a dim night light it's fine. This would actually be important for your own purposes as well, when entering the room while it is dark. Of course by the time the baby reaches toddler stage, there are different things to consider and ways to help the child go to sleep on his own.