My LO still wakes up at least twice in the night. I've been going in and sleeping with her in a bed in her room, so we have a whole host of habits to break.
But with DD1, when she was around 9mths and waking just once in the night to nurse I did the Jay Gordon method. Essentially you reduce how much you allow them to nurse a little bit each night, until they are nursing so little it's not worth them waking up.
We got to the point where I'd count to 10 in my head, and then unlatch her. We did that for 2 nights, after that I just went in and patted her bottom. And after two nights of bottom patting she didn't bother waking.
I like this method because although they don't "need" to nurse in the night, if they're in the habit of having a good drink at night, then they need an opportunity to shift they're feeding so they're making it up at another time. Because although they don't need to eat at night, they're going to feel hungry if that's what they're used to. (In my opinion)
It's not a quick method because it does take a few days of gradually reducing the nursing session, but it suited me and my baby. I figured I'd been waking up for so many months that a few extra nights wouldn't kill me.