Actually, it just comes down to “do what your mamma told you.” Ordinary hygeine, like “wash your hands with soap and water” and “sneeze into your shirt sleeve” and “stay home if you’re running a fever,” are remarkably effective practices. (Soap basically de-constructs a virus particle.)
COVID is a corona-virus, which is a fairly large family of very-mutagenic viruses which (along with rhinoviruses) are responsible for “the common cold” ("a-choo!"), as well as some much-more nasty things. Infections are most commonly spread by contact: you picked up the wrong box of cereal, then you chewed your fingernails, and your immune system was having a bad hair day. Oops.
Mask-wearing, however, really won’t help anything: it might make things worse. Viruses are infinitely too-small to be filtered out by cotton or paper. It’s virtually certain that your mask is by now dirty, and when you’re fiddling with it you’re putting your hands in contact with your eyes, nose and mouth. Don’t make things harder on your immune system than they already are, virtuous though you might intend to be.
We now see that the “human behavior changes” that we attempted to use to counter this pathogen … really didn’t do anything useful at all. “But they looked so good on paper!”
Viruses and bacteria have been an unfortunate part of life on Planet Earth since the dawn of time. We cannot start to live our lives in mortal fear of them, because then we would no longer be living.