How to not get sick during flu season?

What are your go-to hacks to avoid getting sick?

I am travelling in Dezember/January to japan so right during flu season.

To avoid getting sick I plan to do the following:
flu+covid shot 3 weeks before the flight
flight
taking zinc+vitamin c in large amounts 1 week before and during
masking in the plane (except when eating)
masking in stores and public transport

and thats basically it.

Still a bit scared since I got sick during my first trip while doing similiar pre cautions…

what do you advice?

by kiwiinjapan