1. Getting a used car seat without checking that it's safe

2. Placing the car seat in the wrong spot

3. Installing the car seat or buckling up your child the wrong way

4. Reclining your child at the wrong angle

5. Moving to a forward-facing car seat too soon

6. Not removing your child's heavy outer clothes

7. Moving to a booster seat too soon

8. Using a booster seat the wrong way

9. Switching to a seat belt too soon