Don't fall in love with one car. Choose several cars in which you might be interested. If you become set on buying one particular type of car, you lose a lot of negotiating power. This way, if one car isn't in your price range, you can negotiate on another car. This helps avoid being talked into options you may not have budgeted for.
Salespeople know about the euphoric that feeling most people get when they have bought a car.
They will prey on this emotional vulnerability to sell you more items. Dealers also love to pressure you into a supplemental warranty. A basic warranty is usually good enough. It doesn't mean it's better. Avoid buying new models in their first year.