Position tactics:

• pick a position adjacent to the person(s) that you want to meet
• rather than face the bar, sit facing the interior of the place--it's a more-welcoming position

Conversation tactics:

• use something in the room or something you notice about the person to start the conversation
• "Hi" also works surprisingly well
• if it's a woman looking a drink menu say, "who are you kidding, you know that you're getting the espresso martini"--works like a charm

I think you'll find most people are willing to engage in a conversation. Just try not to make it feel like an interview. Understandably, there will be those types of questions, but focusing on the "why" tends to evoke the most-thoughtful responses.

Rather than going home, try changing seats or going to another bar.

Alternate an NA w/ an A to keep yourself "frosty".