Many buyers choose a car without so much as opening a door, but it's extremely important to try before you buy. Most importantly, make sure the car fits you. If you're over six foot tall, there will be cars that simply won't fit. If you're small, there'll be cars in which you can't reach the pedals or the driver's seat won't have enough height adjustment. Choose a make with a reputation for reliability.
Most modern cars are tough, but there are still some with reliability glitches.
If you're in doubt, look at the JD Power Car Satisfaction Survey or the motoring magazines. Check the car is crash-resistant in an accident, again most motoring magazines have crash data. Flexibility is important, too. Make sure your car fits you. People with lots to carry need a people-carrier or a capacious estate.