My ds started to sleep in his own room since he was 3. We slowly progressed from letting him fall asleep in our room and later carrying him to his bed in his room to him falling asleep on his own, in his own bed in his room in about a year. By the time he was 5, he does his own night routine and goes to bed at the designated bedtime. It definitely hasnt been easy, there were lots of digressing esp during stressful periods. like another parent said earlier, consistency is important. It helps to encourage ownership of his room, etc decor, fav toys. Also during trying periods; flashlight, light sticks, twinkling lights etc to make it fun or as distractions.
