unlike what many in the still-COVIDing community may have you believe (where the approach is either "tons of layers of Swiss-cheese protection with dubious-at-best evidence for each" or "I put my mask on any time I even step outdoors" - or both) there's really only one principle that you need to know about preventing COVID transmission.
the only time-and-again proven route of COVID transmission is via aerosols, AKA exhaled vapors from our lungs. inhale enough aerosol saturated with virus, and you'll get COVID. it's a simple equation, and, unfortunately for us, fucking annoying, because so many places we go are saturated with these exhalations. that said, here are a few things that you can do to prevent this transmission route:
MASK UP INDOORS using a good, fit-tested N95/KN95 mask. cloth and surgical masks will not filter aerosols, but (K)N95s will. even in an aerosol-saturated room, chances are you'll be safe if you take this one step.
1A) DON'T TAKE THE DAMN MASK OFF until you're outdoors again. even if you take it off just to eat, that's an an exposure route.
SOURCE CONTROL. good masks are most effective when they're used to stop infectious aerosols at the source. to that end, push for events - especially indoor events - to be mask-required.
CLEAN AND CIRCULATE AIR in indoor spaces using HEPA filters and/or open windows.
MASK UP DURING OUTDOOR CROWDS OR PROLONGED OUTDOOR EXPOSURE TO OTHERS. again, this is a simple equation: inhale enough aerosols and you're infected. aerosols dissipate quickly in outdoor air, even with a gentle breeze (think about a fog machine running indoors versus in an open outdoor space), but you can still inhale enough for an infectious dose if you're close or persistent enough. passing by someone on the street almost certainly isn't going to give you COVID, but sitting at a restaurant unmasked or hanging out amidst a crowd of people outdoors just might.
CONTACT-TRACE, ISOLATE AND TEST if you're going to see someone outside of your bubble unmasked, especially if they don't take precautions themselves.
and... that's it. nothing else needed. no snake-oil mouthwash or nasal sprays, no goggles, no wiping down your food post-grocery store trip, no dubious supplements. just avoid aerosols and chances are* that you'll be fine.