Observe. At whatever age from baby to, older adult, small bites careful chewing appropriate food for age watch children while eating, since they will stuff anything and much in their mouth if allowed good dentition when of age don't talk with full mouth avoid drunkenness, and drugs as older don' be distracted while swallowing as a parent, know basic life support skills from aha heimlich etc.
Keep out of reach. Avoid foods on which a child might choke easily (candy, hot dogs, popcorn, peanuts). Cut food into small pieces, about half the width of a pencil. Store toys in a chest without a dropping lid.