1. Don’t do fascism yourself. (This is harder than you think.)
2. If it is within your power, prevent others from doing fascism.
3. Help others that have had fascism done to them.
4. Grow your power, in order to do #2 more often.

Avoid creating or growing an organization that has a strong hierarchical structure, as they are easier for fascists to convert/infiltrate. https://www.youtube.com/watch?v=agzNANfNlTs Democratic structure can be better, but beware giving any power to the intolerant. https://en.wikipedia.org/wiki/Paradox_of_tolerance#Paradox_of_freedom_and_paradox_of_democracy

If you are comfortable, #4 might involve physical, martial, melee, firearm, etc. training. It is not unlikely that the current fascists in power use violence to grow/retain power, and that might require violence as part of the fight. That said, I feel there’s plenty of non-violent ways to fight fascism, for now.