Give people time to warm up. You can bet others are hoping a conversation will roll, too. Support others you see fishing for conversational topics. Don't stay silent. Once you've hooked some chat, take turns.
Good conversations deepen the subject or move on to related topics.
You might begin discussing salsa, head on to salsa dancing, continue on to guitars. Stay open and creative. Listen and respond, instead of focusing on what you should say next. No fair just asking questions, either. Avoid yammering eternally about your favorite topic.