This was shared in one of the Facebook groups I follow.

“You shouldn’t sleep train at all, before a year, before 6 months, or before 4 months, but if you wait too late, your baby will never be able to sleep without you. College-aged children never need to be nursed, rocked, helped to sleep, so don’t worry about any bad habits. Nursing, rocking, singing, swaddling, etc to sleep are all bad habits and should be stopped immediately. Naps should only be taken in the bed, never in a swing, car seat, stroller, or when worn. Letting them sleep in the car seat or swing will damage their skulls. If your baby has trouble falling asleep in the bed, put them in a swing, car seat, stroller, or wear them. Use the crib only for sleep and keep it free of distractions. If the baby is having trouble adjusting to the crib, have them play in it first. If the baby wakes up at night and wants to play, put fun toys in the crib to distract them.Put the baby in a nursery, bed in your room, in your bed. Co-sleeping is the best way to get sleep, except that it can kill your baby, so never, ever do it. If your baby doesn't die, you will need to bed-share until college. Keep the room warm, but not too warm. Swaddle the baby tightly, but not too tightly. Put them on their backs to sleep, but don't let them be on their backs too long or they will be developmentally delayed. Give them a pacifier to reduce SIDS. Be careful about pacifiers because they can cause nursing problems and stop your baby from sleeping soundly. If your baby sleeps too soundly, they’ll die of SIDS. Don’t let your baby sleep too long, except when they’ve been napping too much, then you should wake them. Never wake a sleeping baby. Any baby problem can be solved by putting them to bed earlier, even if they are waking up too early. If your baby wakes up too early, put them to bed later or cut out a nap. Don’t let them nap after 5 p.m. Sleep begets sleep, so try to get your child to sleep as much as possible. Put the baby to bed awake but drowsy. Don't wake the baby if it fell asleep while nursing. You should start a routine and keep track of everything. Don’t watch the clock. Put them on a schedule. Scheduling will make your life impossible because they will constantly be thrown off of it and you will become a prisoner in your home. Using the "Cry It Out" method (CIO) will make them think they’ve been abandoned and will be eaten by a lion shortly. It also causes brain damage. Not getting enough sleep will cause behavior and mental problems, so be sure to put them to sleep by any means necessary, especially CIO, which is the most effective form. CIO is cruel beyond belief and the only thing that truly works because parents are a distraction. Formula and solid foods will help the baby sleep longer. Solid foods shouldn’t be given at night because they might wake the baby. Don't stop the baby from nursing when asleep. Be wary of night feeds. If you respond too quickly with food or comfort, your baby is manipulating you. Babies can’t manipulate. Babies older than six months can manipulate.Sleep when the baby sleeps. Clean when the baby cleans. Don’t worry. Stress causes your baby stress and a stressed baby won't sleep."