New-parent mistake No. 6: Not properly installing the car seat

Any new parent who’s tried knows that installing a car seat is -- or at least can seem like -- rocket science. “Once you have chosen the right seat,” Walker says, "go to your local fire station or Babies-R-Us or another chain store to make sure you have installed it correctly.” Or go to get help putting it in. "Your infant's life,” she says, “may depend on it."