We struggle to get our daughter to sleep

I can spend up to 5 hours trying to get her to sleep and then I end up falling asleep with her on me. In the daytime she fights sleep and as soon as she notices she's in her cot she gets up and makes A fuss. She's outgrown her rocker and rarely slept much in there too. Also she feeds alot throughout the night and sometimes I end up putting her next to me cos I can barely hold my head up myself. I know it's not best practice to do this, but I am pretty warn out especially on the days she fights sleep throughout the day. I bathe her before bedtime, listen to bedtime songs and read to her non of which really works. The only time she'll sleep in the day is the car or in her pram which is becoming hit and miss too. Any tips?