How has the car been rated? Do your homweork before shopping. What does Consumber Reports say about the car's safety record, reliability and frequency of repair? In addition, Consumer Reports gives the list price and dealer cost of cars, crucial information in negotiating price.
Check car magazines for their performance ratings, bearing in mind that these publications are supported by advertisements from car manufacturers. EPA's "Gas Mileage Guide" (available at car dealers) provides an indication of the relative fuel economy of a given car.
How trustworthy is the dealer? Check with the Office of Consumer Protection and the Better Business Bureau in the car dealer's locality for the number and types of complaints filed against a dealer. How were they resolved? Ask friends who own the make of car you're considering about their experiences and recommendations.
What's the dealer's service record? Is the dealership an AAA "Approved Auto Repair Service"? What does Washington Consumer Checkbook say about customer satisfaction? Are the service department hours convenient; are loaner cars available for lengthy repairs? Can the service facilities be reached by public transportation?
Does the car fit? Try on a car just as you would a new suit or pair of shoes, suggests DOT's "Common Sense in Buying a New Car." The car should fit you physically (Can you reach the pedals comfortably; is there enough headroom; are the seat belts long enough?), and should fit the purposes for which it will primarily be used. (Will it be used for city driving, long vacations, family travel, camping or hauling boats or trailers?)
Test drive. Drive the car over different types of roads and different conditions: highways, windy roads, bumpy streets. If you plan to use the car for family trips, load the kids in the car for the test run. Given the large investment you are making, consider renting the car for a few days before buying, to see how it performs on a day-to-day basis.
If buying a car that's in stock, insist on testing that specific car. Make sure that all minor repairs -- chipped paint, faulty door locks -- are fixed before you leave the dealer. If ordering a car, make sure that the car you receive is exactly as ordered, and that expensive extras haven't been included by mistake.
Be wary of dealers that offer you a car almost like the one you've ordered, rather than your car.
Be wary of "extras" such as "extended warranties" that are really service contracts requiring you to pay additional fees. Read carefully to see what is excluded as well as included. Take all contracts home, think them over and compare.