THE most effective things...WEAR A MASK, and WASH YOUR HANDS.
By "flu season", we will have an adequate supply of commercial masks and plenty of hand sanitizer. The Italian subsidiary of the firm my wife works for got through their crisis with NO DEATHS just by stringent application of those two things.
The whole "masks don't work" meme is bullshit and probably originated in a Chinese disinformation tactic.
I wear a mask when I go inside stores. Not a big deal.
The way most everyone selects, applies/fit tests, wears and/or maintains a mask renders the face/identity cover no more effective than carrying a handkerchief in your back pocket. And without fitted goggles to protect the eyes the wearer is completely unprotected. Your contention that China is responsible for this scientific and practical reality is inane ... it’s the users of the masks who are responsible for the failure of their personal protective equipment to effectively serve its intended purpose.