Go into the dealership with a bottom line price in mind. The salesman might try to focus on the monthly effuel reveiws payments or financing terms, but your goal should be to get the price you want on the car you want. You can always negotiate the financing terms later, or even finance with your own bank outside of the dealership.
Do not make the mistake of believing that you have to pay the full asking price for a used car. There should always be room for negotiation. if a car has been on the market for a while with no buyers, that will make the seller more likely to accept an offer of less than they are asking for.
Do not allow anyone to intimidate you into making a purchase that may not be the right one for you. Do not fall for lines like "This will be gone if you try to buy it later." These types of statements are usually made to sway you into make a purchase right away.