My algorithm:

1. Start by saying something, something neutral/positive or a compliment: "Nice weather, eh?", "Great party!", "Nice tie"

2. Ask questions: "How are you doing ?", "What brought you here ?", "What line of work are you in ?"

3. Repeat #2 until you find something that you have something to say about. Could be that you discover you're in the same line of work, grew up in the same town, etc

4. Keep your talking time to 50% or less, be sure to throw in questions here and there and respond to the answers.

5. Profit !

I love this approach. Step 4 is key. I've found tremendous success simply asking questions about what people do, their interests & opinions, etc.

It's cliche but it's true: "Interested people are interesting."

Here's another question for your repertoire (that I picked up from someone else): "What's been keeping you busy lately?"