Sleep Schedule Tips - How Do I Get My 4 Month Old on a Schedule?

Been trying to get our daughter on some kind of consistent sleep schedule and it's been rough. Right now she's all over the place - sleeping at weird times, up at 2am, sleeping through part of the day. I know some babies just do their own thing but I feel like having some kind of routine would help both of us. Anyone have success with sleep training? What method did you use? Don't want to do cry it out but willing to try other stuff. Just need some structure here.