It's a fact of life: Some babies are naturally good sleepers and don't need a lot of intervention to sleep through the night; others need more soothing and support to make it happen.
By the time your baby is 4 months (and at least 14 pounds) he's capable of getting enough nourishment during the day that he no longer needs to eat in the middle of the night. So the first thing you should do is drop the middle-of-the-night feeding if you're still giving one. Remember, just because your baby wakes up to eat doesn't mean he's hungry -- it means he's trained to do that, and it's up to you to break the habit. To prep baby for this transition, don't allow him to nod off while he's nursing or taking a bottle (otherwise he'll associate falling asleep with eating). Instead, cuddle him for a few minutes after he eats and then put him down when he's awake. Sometimes offering a pacifier can help your baby settle himself and ease the transition off the nighttime bottle. When he wakes in the middle of the night (which he likely will do), avoid feeding him. You can comfort him with a quick, whispered "Everything is okay. Time for sleep." The more intense the interaction in the middle of the night, the more stimulating and rewarding, making it harder for him to settle back to sleep, so keep it low-key. If you are consistent in this approach, he'll get the message that the all-night diner is closed.
If nighttime feeding isn't the issue, perhaps your baby is having a hard time soothing himself back to sleep when he wakes in the middle of the night. All babies wake up in the middle of the night, but some are better at falling back asleep on their own than others. To teach your baby this skill, it's important that you don't rock him to sleep in your arms, although we know how tempting it is. Imagine his surprise (and separation anxiety) when he wakes up all alone in the dark after falling asleep in Mommy's arms -- of course he cries for you! Instead, put your baby down when he's sleepy but awake.
It's also possible that your baby is on the verge of a major milestone. For example, when babies are learning how to sit up, they often don't sleep as well because now that they can get themselves up into this position, it's harder to settle back down. Follow these simple strategies to cope with the crying for the first week or two:
• When your baby wakes up crying or can't fall back asleep, wait five to 10 minutes to give him a chance to settle down on his own. After that, go to him and offer reassurance, but keep your interaction to a minimum. Avoid picking him up, turning on the lights, offering toys, or speaking in an overly animated voice.
• If you find your baby upright in his crib, lay him back down and gently rub his back for a few minutes.
• Put things around your baby's crib to soothe and divert him, like a crib-safe mirror, a ceiling fan, or a crib aquarium that makes bubbling underwater noises. For safety reasons, make sure any toys in the crib are attached to the bars.
• Repeat the process as often as needed throughout the night. Most babies take a week or two to figure out how to conk back out on their own.