My favorite tactic has been to take public transportation (a requirement, for me) and both strike up and respond to conversations around me. Sure, most people are isolated and in their own little world, and it's not something I do every day, but it's good practice for learning how to open someone up to talk with, and then keeping it going. And if you bungle really badly, it's not that likely you'll see them again.
To practice at listening, challenge yourself to go home after that and write down the conversation verbatim, or at least the gist of what was talked about.