How do I protect my 6-month-old from choking and suffocation?

Small bites. If normal activity and eating, small bites and careful observation the airway has some self protection and while sitting up is better generally after one can. Read the aha material on choking and know what to do if it happens to anyone- adult or child- it is life saving.
Keep out of reach. Cords, ropes, or strings around the baby's neck can choke him. Keep cords away from the crib. Keep all small, hard objects out of reach. Use only unbreakable toys without sharp edges or small parts that can come loose. Avoid foods on which a child might choke (such as candy, hot dogs, peanuts, popcorn).