OP, successful BFing after a bad expererience can be done and I really believe being pigheaded determined about it is an important first step.
After 2 middling to poor attempts as BFing DS1 and 2 I was hellbent on giving DS3 the best shot I could at BFing:
1 I did not leave hospital until I thought latch was ok (48 hrs after totally normal vag delivery)
2 When he cried I always offered breast first before trying to figure out if he wanted something else - usually he didn't
3 I had arranged my life before the birth to allow for as much time as possible spent with BFing him: DSs1 and 2 still went ot childminder a couple of days a week, freezer was fully stocked with precooked/TV dinners, cleaner continued even though I was on mat leave etc.
4 I had a special box of toys/sparkly crayons that only came out when I was Bfing, which was a great success with the older 2.
5 I had made sure I had all sorts of contacts to various different BFing support agencies: LLL, BFN, local hospital, community volunteers, BF support group. And I did pester not hesitate to contact them. I had some supply problems and problems with blocked ducts/glands (with hindsight maybe poor milktransfer from breast to baby??) and I really really used the service, a lot .
6 I tried v hard to not look further forward than the next feed or may the next day, as in "I'll just feed him again next time, and then we'll see". The initial goal I had set myself was 6 weeks, then 3 months, then 6, and after that it was soooo much easier than anything else we just continued and I did not think about it much at all. We stopped (gradually) at 13-14 months because I wanted to wear decent bras again and he was not terribly interested anymore.
I hope some of this will help you. Yes, the older 2 watched a lot of TV but I was also lucky that they had each other I suppose. I am hoping to do it all again next year, oh gawd... !!
Oh, and yes, a ringsling is great for feeding on the go when baby is tiny; I found it harder with a bigger/heavier child.
Good luck to you, I hope you have a good experience this time.