Background: I'm looking at buying a used 2012 - 2013 Honda Civic from a dealership. This is my first ever car purchase, and with my lack of knowledge I am concerned that I will overpay in negotiations.
For the purposes of this question, let's leave it as generic as possible. Assume normal conditions (stable market, no accidents, fair car condition, good credit, etc).
Question: How much off list can I reasonably expect to get from a dealership?
For instance, are the KBB (Kelly Blue Book) upper and lower bounds pretty much absolute, or is it advisable to go even lower than that? Is there a common rule of thumb that applies to figuring out the lowest possible value for a car, so I have a good target in mind going into the negotiation.