I never wear open-toed shoes on a flight - I was on a trip with some girls from university who wore flip flops and sort of laughed at me for that (one wore flip flops with 2" or 3" heels)... I'm tempted to call them up and say "see? I'm not crazy."

Natural fibres are the best to wear, and count the seats from your exit rows. I always know how far I have to go ahead, and how far I have to go back in case one way is blocked... don't just know the closest, but know the one in the opposite direction as well.

I think a respiratory mask would be a bit extreme... but if you want to haul one around, it may help.