Possible Clues:

• Start a conversation
• Get a party going
• Crack a little joke
• Get a delicate dialogue started ... and a hint to 17-, 25-, 34- and 49-Across
• Start a friendship, in a way
• Begin a conversation, and what the answers to the starred clues do to their circled letters?
• Warm things up, and what 17-, 28- and 50-Across literally do
• Introduce one's self
• Perhaps get techie to relieve tension
• Overcome unfamiliarity