This was DS1. He has never been a very good sleeper and still isn't great at 4.5 years.
At about a year, I started letting him cry-it-out a bit. I wasn't comfortable with just letting him cry to sleep, but I did find that if I let him fuss/cry for 5-10 minutes, he'd go back to sleep. I now think I was a big contributer to his sleep issues by going in too quickly.
Another thing that worked for me was to cut down the nursing sessions by 1 minute each night so he got less and less. After a couple weeks, he stopped waking for a few of them. Got too used to a full tummy at night!