There are rules for first contact with aliens. And a place to meet aliens where the rules are enforced. Simple things like avoiding smelly bodily emissions, even if your race considers them a compliment, and complicated things like not asking another race if they are edible. Feel free to read up on the rules of the First Contact Cafe, then pull up a bar stool, or a pool of sludge, have a drink of beer or get high on methane, and plan your next trade...