A recent study published in the Journal of Pediatrics offers some really sobering data: Of the children who died in a car crash from 2010-2014, 20% were not buckled at all or the seat belts were fastened incorrectly.
Most of the deaths occurred in the South. The rates varied quite a bit from state to state. Since those states which have better regulations regarding seat belt use seemed to fare better, it is imperative that states tighten up seat belt regulations.
Seat belt use is at its highest level since 1994, but if the seat belts are not fastened correctly, then the risk of a fatal outcome increases dramatically.
Children should not sit in the front seat. Car seats depending on the age and weight should be placed either facing forward or backward. Even correctly securing the car seat can be confusing.
The best way would be to have an expert show you how to do it correctly. Car dealerships will know the correct ways. Looking it up on say Youtube is good, as long as you trust the source. The CDC or Center for Disease Control offers excellent advice on its website.
Interestingly, those states with red light cameras at intersections had fewer deaths. These cameras are used to enforce stoplights and might be causing drivers to slow down and stop during a red light.