Approaching for the first time someone you don’t know: focus on them, ask about them and approach humbly.
Deciding when to end a conversation: you can end the conversation by excusing yourself and saying you have something that needs to be attended to.
Awkward silences: knowing when to shift to another topic, introducing a new person to the conversation or even having a few conversation-continuers at the ready can help.
Accidentally saying something inappropriate: apologize quickly, admit the embarrassment, and, if you mean it, apologize without excuses. Trying to smooth it over will dig the hole deeper.
When someone else says something inappropriate: by diffusing the situation, and redirecting the conversation. Practicing active listening reveals when to intervene.