I think for me if was being in hospital in a way that was out of my control zxx having a bad experience (when I had my son).
Before then I saw hospital both psych and general as a place to be cared for and looked after when I felt I wasn't getting that at home or myself. I realised that I had to learn care for myself and the thought of stepping into a hospital again fills me dread. I suppose that safety blanket was taken away.
I know you can't do this and it's nothing i actually did myself but the first step I think I took was listening to people when they said I was worth something and what had happened in my life was not my fault. I think I only ever had 1 person in my whole life who when I said "...what happened in my life was my fault" and "I'm horrible/evil/anything negative." Compare that to the shed load of perfessionals/friends/ even police when it was explained why I was being unhelpful. I used to be told to look at the evidence as to why it wasn't my fault and I didn't want to do it I was stuck in my self hate bubble tbh I still haven't researched it. But eventually it will chip away at you and you will start to think "why are all these people so definite I am wrong" and just that one thought if you say it to yourself everytime you think something negative to yourself then it starts to really slowly make you believe it and you get to this point eventually where the good voice is louder then that negative one.
Also accepting that the past cannot be changed no matter how much you want it to be and thinking about it will only upset you. I think I was stuck in the past because I was so afraid of the future and it sounds corny but take every day as it comes..people love you and will support no matter how hard it gets and we are lucky to have that.
I think the thing that makes it so hard to move forward is the fear of failing and letting go of the option to kill yourself/hurt yourself but while that option is still in anyone's head it's virtually impossible to start living fully.
It will always be difficult at times but you can do it!! You are worth so so much more then what you think you are now and it is NOT big headed to think your a good person... I'm still at an "ok person" stage but even that is better then "evil/stupid/whatever"