Try getting into a set routine every night. Whether it's reading a story, bath, brushing teeth...just do the SAME things EVERY night and in the same order. That helps the baby get into the habit that okay, i read a story, then I go to bed.

How old is he/she? I might have missed that.

You can also try white noise - like a fan, or humidifier...that constant humming sound can help some kids.

Other than that, you already got some good suggestions above. Good luck.