Honestly, in our personalized consultations, we try to avoid this method as much as possible. If you are going to use cry it out, we recommend your baby is at least 6 months old, but preferably 10 months or older, when we expect almost all babies to be able to get through the night without a feeding. It is not for the faint at heart. We find that laying a foundation in the beginning with other strategies and techniques can reduce crying even if this method is used in the end, however.
"By the time your baby is 3 months old and has developed a fairly predictable 24-hour pattern, it becomes more important for you to provide increasingly consistent structure. If you do your best to establish a reasonable and consistent daily routine and keep to it as much as possible, then it is likely that your child will continue to develop good patterns. If instead you allow the times of your child's feedings, playtimes, baths, and other activities to change constantly, chances are his sleep will become irregular as well."
Typically, formula-fed infants who are growing well no longer need to feed at night by 6 months. Breastfed infants may continue a little bit longer, but typically no longer feed at night by 9 months. If your baby has been falling asleep independently at bedtime for a month but still waking to feed, you may want to consider weaning at night. Be aware that if you are breastfeeding, this may lead to a reduction in milk supply.
There are many different sleep training methods to choose from, but the most common methods are one of or a variation of one the five we've explained below. You might find that one of these methods sounds like it would be a perfect match for you, OR you might find aspects from each plan that you like. Just like Melissa said, don't feel like you need to stick to a certain method 100%. Make the plan work for you! 
Some experts suggest techniques that are slightly different than these methods. Perhaps the best known is pediatrician Harvey Karp, author of The Happiest Baby on the Block. His method suggests a very specific routine involving the so-called five S's: swaddling, the side or stomach position (for calming your baby, not for sleeping), shushing, swinging, and sucking.
Sleep experts who support the cry it out approach (as well as most pediatricians) disagree. They say it isn't traumatic for babies to cry alone for short periods of time with frequent check-ins by Mom or Dad – and the end result is a well-rested, happier child. They say no tears sleep strategies may cause babies to be overly dependent on comfort from a parent at bedtime, making it harder for them to learn to soothe themselves to sleep.

“There are many variations to any sleep training method. For example, you can do a cross between The Chair Method and PUPD with great success and fewer tears! There are also ways of breaking each method into smaller baby steps, which we recommend very often in our Personalized Sleep Plans®. Find what feels tolerable (because, frankly, no one ‘likes’ to sleep train), more comfortable for you, and what seems the gentlest, yet effective, on your baby, depending on his or her temperament and personality.”

“You’ll never sleep again.” Sound familiar? There’s a reason this cliche is often repeated at baby showers: In those first few months of parenting, before baby has an established sleep-wake cycle and needs to be fed only every few hours, sleep is fractured and confusing, with a long stretch just as likely to occur midafternoon as it is in the middle of the night. And that’s normal. But once baby is a few months old—after she’s dropped those middle-of-the-night feedings and has established a somewhat predictable sleep-wake cycle—sleep training her can help your whole family get some much-needed nighttime shut-eye. Here, what you need to know before choosing the best sleep-training method for your family.
It might be strange to think of sleeping as a skill that does not come naturally. As a new parent, you’re probably so exhausted that you pass out as soon as your head hits the pillow. Your baby, however, doesn’t have this same ability yet. Although they spend a lot of time sleeping, they need to learn when to sleep (day vs. night) and how to sleep. Until they do, they need your assistance, which is why you (as you should) help soothe them to sleep at bedtime and comfort them when they wake in the middle of the night. Sleep training is teaching your baby how to sleep without any help from you - just like you’re able to fall asleep without anyone there to help you do it.
Simply put, sleep training—also called sleep teaching or sleep learning—is the process of helping your infant learn how to fall asleep and stay asleep. It’s also become a pretty controversial topic, with experts and parents speaking for or against various sleep-training techniques. “It’s like talking politics,” says TJ Gold, MD, a pediatrician at Tribeca Pediatrics in New York City. “But there’s no one right way to get your child to sleep through the night. There are a lot of different ways.”
With the fading technique, continue with whatever method you were using to help your baby fall asleep (such as rocking or nursing), but decrease the amount of time you spend doing it until, in theory, you don’t have to do it at all. This is a great technique for minimizing crying, but unfortunately, many parents find it difficult to sustain. “There has to be an end in sight,” explains Mitelman. “For example, we’ll meet this need for five to seven days and then we’ll pull back a little bit.” But if you’re willing to stick to the plan and get your baby to the end goal of going to bed without your assistance, Mitelman says it’s worth a try. “Whichever way the child can get to sleep independently is fine because that’s the key ingredient to sleeping through the night.”
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