Good safety rating
Every seat on the market meets the minimum safety standards, but you'll want the safest car seat you can find, especially if you have an older car. Generally, higher-priced models are more expensive because of their extra attention to safety features like head cushioning and side-impact protection.
Easiest installation
If your car is LATCH-equipped, you won't have to worry as much about proper installation. However, if your car seat isn't LATCH-equipped, you should at least make sure that it's reasonably easy to install with confidence. It is important to note that proper installation is the key to a safe car seat.
Five-point harness
This harness secures your child in place at the shoulders, hips, and between the legs for maximum security and is a standard feature in every car seat.
Front harness adjusters
Adjusting a harness in the back is like doing it with your eyes closed, so ensure you are able to adjust it from the front, especially considering you'll have to do it every time you put your baby in the car.
Removable/washable fabric and pads
Your car seat is definitely going to get dirty, so look for removable and washable pads and upholstery.