How to get baby to sleep through the night?

Ok I need some help mommas. My daughter just turn one and isnt sleeping thought the night. She use to no problem but for the last 2 months so not any more. She wakes up at less 3 times ever night. She goes to sleep about 830ish and will sleep till at 230 and then that when she is up on and off till 730. I just don’t know what to do any more. What can I do to help her sleep though the night