Car seats are awesome. They save lives and prevent injury. Some even have cup holders so our kids never have to be without their sippy cup. But car seats can be difficult. So difficult, in fact, that according to Safe Kids Connecticut, four out of five are installed incorrectly. This isn't just dangerous — it's deadly. According to the National Highway Traffic Safety Administration (NHTSA), car crashes are the No. 1 killer of children ages 1 to 12 in the United States. Installing your child's car seat correctly really can mean the difference between life and death. Don't just assume your child's seat is installed right. Be sure of it.

1. Size It

Every car seat is made for children of a specific size. Finding the right one for your child will mean your child is comfortable and safe. Check each seat to make sure it's the right size before you get it home.

Not only does the seat have to fit your child, it has to fit your car. My family had this problem when we bought a new car. Our infant seat didn't quite fit right in the new van. Before you leave the store with a car seat, ask if you can test their floor model out in your car first. They should say yes. If they say no, find a different store.

2. Read It

The first step in mastering the car seat is to read and follow the directions. You may think this is a given, but a survey by the NHTSA found that one in five parents don't read any instructions when installing a car seat. It's one of the most important items you will ever install or use in your life, so before you even attempt to get it in your car, please read those directions!

3. Attach It

Your child's seat must be attached correctly. This means using the LATCH (lower anchors and tethers for children) system correctly, according to your seat's instructions, or using the seat belt correctly according to your seat's directions. Don't use both. The car seat should not move more than an inch from side to side once installed. The seat also must be at the correct angle as stated in the instructions.

4. Harness It

The harness is probably the most important part of your child's car seat. Even if the seat itself is installed correctly, improperly harnessing your child into the seat can leave your child very vulnerable in the event of an accident. Make sure you are using the correct harness slot for your child. The harness slot will have to be changed as your child grows, so don't forget to keep checking it. The harness chest clip must be placed over your child's chest — not her abdomen, not her throat. Placing the clip over the abdomen can cause internal injuries in a car accident. In addition, the harness needs to be tight. There should be NO slack at all.

In addition to taking these proper steps, you should always research a car seat and never buy a used one. You don't know for sure if a used seat has ever been involved in an accident before, and those that have are no longer safe. Always make sure your child is facing the right direction for her seat and her size and never buckle your child into her seat in bulky clothing, as the harness will not fit right. Once you are sure you have the seat installed correctly, take it to an inspection center to have it double-checked. Your child's safety is worth the effort.