At this young age, rocking, feeding, or petting your baby is good because you won't be creating negative sleep associations that need to be corrected later. Your goal is to put the baby to sleep.
1. Do what works.
Remember, a lot changes for your baby, so try, at least for now, to "go with the flow." This could mean your baby naps in a swing, stroller, or car so they can sleep during the day. What worked yesterday may not work well today, so be prepared to try a few different options for 4 month sleep regression via babysleepmagic.com/blogs/resources/the-4-month-sleep-regression.
2. Pay attention to your baby's sleep signals and try to respond quickly.
Depending on your baby, their sleepiness signals can range from subtle to extreme. Look for things like yawning, disinterest, rubbing your eyes, and increasing excitement.
3. Be careful when making new sleeping crutches.
This can be tough advice to follow when both of you are desperate for sleep. If you're used to rocking your baby to sleep, continue rocking him, but don't add his food to the sleep mix. Even if your bedtime routine includes eating and petting, that's fine, but don't add swaying to sleep.
4. Look for signs of growth.
Yes, it's a tough time, but you'll be amazed at the new discoveries your baby will be making these weeks. You may find that your baby is learning to turn, or may begin to master the sitting position.
5. Follow your flexible schedule as much as possible.
Babies thrive on consistency and routine, so make sure it's available to them. If you haven't already, this is a great time to create a relaxing, relaxing bedtime routine of 3-4 items (like a book, a song, the bathroom, then your bed) that you can use before bed.