It's common to hear promises of a method that 'fixes' a newborn's sleep in a few days. In practice, sleep this early is physiologically irregular — the baby can't yet tell day from night, and sleep cycles are short (30 to 50 minutes) compared with an adult's.
What to observe instead of forcing a schedule
Sleep cues usually appear before crying: a 'faraway' look, rubbing the eyes, yawning, getting quieter. Using this window to put the baby down to sleep usually works better than waiting for overtired crying, which is already a late sign.
Short, repetitive routines (a bath, a darker room, a song) help the baby associate these cues with sleep over time — but it's a gradual process over months, not an on/off switch.
Safe sleep
Widely accepted pediatric recommendations include: putting the baby to sleep on their back, on a firm surface, without pillows, crib bumpers, stuffed toys or loose blankets in the crib, and sharing the room (not the bed) with the parents in the first six months. These practices reduce the risk of sudden infant death.