What worked for us was converting her crib to a full size bed, we put up the railing on the side and I would lay with her until she fell asleep and after a week she could put herself to sleep. She sleeps through the night now and won’t sleep anywhere but her bed, she was a crazy sleeper so her constantly hitting her legs or arms on the crib would wake her up. I also took her to target and let her pick out a comforter and made a huge deal out of her “big girl bed”
I read the No Cry Sleep Solution. Despite the name it felt like a good compromise between Cry It Out and constantly comforting her. I think they have a toddler's version, too. I just checked it out from the library app on my phone. She's not a perfect sleeper, but usually only wakes up once or twice during the night now and just needs to be covered up or needs her water found or something and goes right back out. PM me if you have more questions or anything!
I started out with his bed being in my room. I put him in there for naps only got about a month. Then one night I put him in there every night and read him a story. He would get up in the middle of the night for a weeks but now he only sleeps in there.
@apples I did that with her when she was about 2 also. It's best to get them used to it young and have them develop a sense of independence so they can develop that problem solving skills and such. It can be hard because you have the urge to run to them when they cry but they need to learn to manage their emotions themselves at some point