Know your material cold
Run the set out loud three times before leaving. Nerves erase short-term memory - practise until the words arrive without you thinking about them.
Bring a notebook and a pen
Write down what got a laugh, what died, and anything you improvised. Two minutes of notes after the set is worth an hour of guessing the next day.
Cash for a drink
Bar-based mics survive on drink sales. Buy at least one. It also stops you feeling like you owe the room anything.
A friend, or no one
One supportive friend is fine. A group that only laughs at you distorts your read of the room.
