We just did a sort of hybrid of PUPD / CIO. Largely because 11mo DD isn't particularly comforted by being picked up, so holding her tends to be a modified version of CIO, if you see what I mean. Some resources say that it is enormously different for a baby to cry when held than be left to cry... who knows if that's true, DD seems to be pretty pissed off either way, but I could never leave her crying in a room alone, even for timed intervals. My instinct is to be there with her.
Anyway. She was waking in the night to be fed (BF until 6mo, bottle from then), at 10mo she had never slept through (though she always self settled for naps fine). She is 11mo now and we've just about cracked it. It has taken a few months because I wanted to be gentle (and we had a big move across the world, which made it difficult).
So, briefly - first, I read the first bit of Dr Ferber's Solve Your Child's SLeep Problems on the advice of my GP. Ferber gets a bad rap because he is a bit of a cold fish - would leave a child to cry until they vomit
. Not my scene BUT the chapters on the science of sleep were enormously helpful. I got a good grasp of sleep cycles and crucially sleep associations and felt entirely less like I was losing my mind. It gave me the confidence to go my own route with DD. I would recommend the first few chapters (get it from the library) wholeheartedly.
I then spent a good month reducing her milk right down, from 6-10 oz overnight spread between three wakings to a bare ounce (same number of wakings, if not more). Then started offering water before milk (but gave her milk as a last resort, though often sucking on the water bottle would soothe her). Then (from a few days ago) just offering water, committed to no milk at all - this meant a few bouts of crying, at bedtime and in the night, I always went straight to her and talked to her, soothed her, picked her up, resettled her. And now, settling her with no help from the bottle. Again, some bouts of crying. But last night she woke briefly at 11pm and settled virtually by herself (DH went into the room and she turned over and went back to sleep) and then slept til 7.30am. This is a fucking miracle in this house, I can tell you.
Other thoughts:
If you're not up for cosleeping, I would crack the cot in the daytime, using gradual retreat method, she simply has to get used to being in there. We did this with DD at about 3mo and she was much easier to settle in the day, and once she was ok in the cot in the day the nights followed (though sadly not the sleep!).
Second, consider that if you are BF and DH is SAHP she might be reverse cycling kellymom.com/bf/normal/reverse-cycling/
Last, look at this thread: www.mumsnet.com/Talk/sleep/a1394888-What-worked-for-us-Hope-this-helps which another poster reposted for me a few days back and helped me to take a confident approach. It is basically gradual retreat and lots of other insight in other posters' comments.
Sorry for the long post! good luck.