My 7 month old pulled like crazy. I started stopping and making him sit and wait till I gave him the heal command. Every time he started pulling I would give him the heal command and if he didn't stop pulling I would make him sit again. It was a long process that first walk but he is now doing awesome and very rarely pulls.
my suggestion ^^ try taking his favorite toy with you and use it to keep his focus on you so he doesn't pull toward other things. Penny has a rubber squirrel with a squeaker that could wake the dead. Keeps attention like a charm and was a great tool on walking etiquette