Think about how much time and energy you're willing to invest in the search. Allow yourself plenty of time when shopping. Dealers can tell if you're anxious and needed a car yesterday. If you still want the car, and the seller is inflexible about price, see if you can get some little extras, such as floor mats or other aftermarket goodies. Speaking of extras, most dealers will try to sell you all sorts of extended warranties and the like.
Most cars come with good warranties.
Don't fall for the notion that you need another. If there are extras you might want, tell the dealer you'd like to think about it. Agree to nothing more than what you really want. Most dealers will give you 30 days to add extras for the price that was originally offered. As with anything that's technical and expensive, it's crucial that know your facts and your product well.