You have to be the one who moves the conversation from chit-chat about the weather to interesting topics. Sure, it's fine to show up to a dev meeting and chat about your favorite APIs and all, but that won't help you make friends.

The vague process chart I personally use looks like this:

1. Determine if you share common interests with the person (eg, small talk about things you do)

2. Talk at a higher level about a single interest. A good trick is to treat the other person a bit like an expert about that interest - "Oh, what board game would you recommend for X?"

3. Make an offer to hangout in the future. It should be in a situation with multiple people and a public place. You're not trying to invite them to a date, but instead communicate that you're already doing something and want them to join: "Hey, I hang out Tuesdays with some folks at the comicbook shop and play boardgames. You should come join us."

4. If the person finds that agreeable or reciprocates, exchange contact info. I usually just hand them my phone with my contact info on the screen so they can choose their preferred method, but you can also give them a personal card.

Congrats, you've now made a new person you know. Hang out with them, invite them to things. Relationships are like gardens, they require regular tending and maintenance at first but as they get established, they only need occasional check-ins.