It sounds like you're already putting yourself out there and being friendly and chatting. Sometimes you just need to really go an extra step. I met a few moms around my neighborhood but didn't strongly click until one mom was VERY on-the-ball about scheduling visits. Not "let's meet up one day," but "let's meet at the playground at 1 p.m. on Tuesday" ... that kind of thing. Some people will say no or brush you off but when you find someone who's willing to repeatedly visit with you, you'll be better able to build a lasting friendship.