Ok, first of all, I do things a little bit differently than other people because I approach these issues with a training/behavioral style instead. I have a background in wild animal training and behavior. I know, sounds weird but it usually works. I weaned both my children at 15 months and it was sad to see that part of our relationship go but it worked. Every child is different, so you have to figure out what works best for your child.
My daughter was easy. I was feeding her for about 30 minutes at night. I started one night, just feeding like normal. A few nights later, I cut back the time by 5 minutes. Then a few nights later, I cut back again. It was making my milk supply go down and it was making it less enjoyable for her to be cut off. By the time we got down to 5 minutes, it was not worth it to her and she pushed me away, pointed to her bed, and went to sleep. That was it, done.
My son was a lot harder though because he really LOVED nursing. I tried the cut back method and he was not going for it. Fought me the whole way. I would go in and pat him on the back and he would get even angrier. So, I had to think a lot harder. I came up with the obvious, he is not hungry but he is waking up at 3 am out of habit and he wants to be comforted. So, it is not actually him that has to be shown how to go to back to sleep on his own but his stomach that has to be trained not to wake him up. I know a lot of books and people say "DO NOT PICK THEM UP", yea, I ignored that. He needs to get back to sleep without feeding, so his stomach does not grumble out of habit at 3 am and wake him up. So, at 3 am he would wake up, I would go in and pick him up. We would sit in the chair together and I would hold him until he fell back to sleep. The first night he was not too happy and I have to admit, I did not get a lot of sleep that night, but he finally fell back to sleep and I laid him back down. I did the same the next night and the next (each night him falling back to sleep quicker and quicker). By the fourth night, he did not wake up and slept through the whole night! I couldn't believe it, it actually worked! I let things alone for a while to get him used to sleeping the whole night and a month later, I worked on the bedtime feeding.
Don't always go by books or what other people say "not to do". You know your kids that best and sometimes, non-conventional ways work. Feel free to try either of my ways but you might also have to tweak it here and there to fit your child and their needs. I know when I felt like I was never going to sleep through the night, I just had to find something to comfort myself. I just kept telling myself that he is not going to be nursing at 20 years old! LOL It will eventually work itself out. Best of luck and I hope you find something that works for you!