Bedtime routine

Any advice on how to get a baby to sleep? She's 5 months old soon to be 6. And is exclusively breastfed..she uses me as her comfort and doesn't have a dummy she won't take to them or bottles. I have been safely co-sleeping but are wanting to put her in her own cot now as she's getting older and try to get her into a routine but where do I start. I've tried everything but I end up giving her the boob and she hogs it all night I've never been able to leave the room for more than 5 minutes before her waking up and screaming. But she needs a routine. Any help would be appreciated x