What age can this start ? Infants should be allowed to settle fairly early - about 2 - 3 months by themselves.
Preparation Make sure you have a supportive partner. There is nothing better than tag teaming an infant sleep problem. The biggest problem here is often the husband who's tolerance for the crying is not quite as strong. At least get your partner to read this.
assume you and your infant are well and healthy before embarking on any sleep program
It would be advisable to start this during the daytime sleep.
If you have close or nosy neighbours then warn them or pick a time they are not around. It is not good to have the police or child protection agency turning up at 3 in the morning.
Bedtime Routine: place infant down awake. For all the sleep related problems a routine is essential. Make sure the routine is the same each sleep. Same sleeping place same noise levels and feeding patterns around this. The order is not important but the most important point here is to put your infant down awake. Do not wait until the infant is asleep on the breast or bottle and then place in the cot. Start this with the day time sleeps.
Remember
Your infant must have sleep to survive. S/he will eventually fall asleep if done properly. If your infant is rewarded for crying by being picked up and reassured or patted then as soon as this association stops s/he will wake again at the light sleep phase.
allow your child to fall asleep without any association
A routine is essential for a good sleep pattern
Sleep is essential for growth, health and development
Allowing your child to cry does no lead to later problems such as insecurities, emotional or behavioural problems
If done properly sleep management takes 3-7 nights
Be consistent. Make sure your partner knows what is going on and will help and support you . If one of you do not think they can do it then organise for them to go away for those evenings.
Choose a time when the children are healthy and more importantly you are healthy.
Warn other house members and even neighbours that you are getting your child to sleep by himself and there will be some screaming and crying.
If old enough explain to your child what you are doing and with comments like - ' Tonight because you are such a big girl you can stay all night in your own bed' etc.
Reward with praise and encouragement.
Make sure you are ignoring or penalising unacceptable night - time behaviour.
Above all be persistent.If you have had no signs of success after 5 nights something is wrong with your technique.
If your child argues about bed time then set an alarm clock. "Infortunately sweetheart the alarm clock says it is bedtime" Therefore the alarm clock is the ogre not you!