My baby girl is 20 months old and doesnt sleep well. she is restless throughout the night and wakes up multiple times. is there anything we can do to help her.

Basics: Avoid patterns that complicate this. A pre sleep ritual should avoid any feeds, drinks, etc. that she cannot self replicate in the night. No cuddles & rocking to go down. If needed read to her from a distance & tuck her in. All kids sleep in cycles. If they learn how to go down on their own (like they did in the womb) they can later.