I posted this in response to another thread, but it's relevant to you:
I have a 10 month old who has never been a great sleeper, but things are dramatically better and I was in your situation months ago where my boy would wake hourly and would scream until I fed him to sleep.
At around 6 months, my boy would feed so much at night, that he hardly fed in the day and would go 8-10 hours in the day without feeding, but want to feed hourly at night. We managed to reverse this - but it took 10 days and a lot of support from my partner but I look back and I think it was the right thing to do as we were so sleep deprived I was crying nearly every day from the misery of severe tiredness and life was miserable. I couldn't enjoy being a mum as I was just simply too tired. Too tired to play with my baby and I spent every second just counting down until the next nap so that I could sleep.
I decided that my aim was to reduce feeding to what would be considered a normal or even generous amount of feeds for a baby of this age (bedtime feed, dream feed around 10pm before I went to bed and one night feed). If baby woke and cried, we cuddled him, comforted him but I only fed him if it had been 3 hours or more since the last feed. Slowly I extended this time period from the 10pm dream feed until the next feed. This required lots of cuddles and our baby did cry, but we comforted him during his cries and he was never alone. We managed to reverse his feeding and he fell into a pattern of dream feed and one night feed - sleeping well in-between. It was bliss in comparison to before.
During these 10 days, it worked much better if I was in another room and my partner tried to comfort him. We chose to start this on a long weekend when my partner was off work, but when he went back to work, I had to do some of the comforting so that he could get better sleep - but by that point we were over the worst and he wasn't waking until about 2 am for a feed.
I should add that my baby had a dummy and this was very useful in helping him to settle as he is one of those babies who gets a lot of comfort from sucking.