I won't say just vote, but you should do that, too, at every level!
Depending on how much time and money you have:
- Join a union (and give time and money to organising the union)
- Join an antifascist political party (and give time and money to organising the party)
- Lobby your representatives to demand they oppose fascism
- Join protests against fascism
- Join civil society groups that are antifascist (either directly or because they're pro human rights or anti-racist, or what-have-you) (and give time and money etc.)
- Boycott businesses that are owned by or enable fascists
- Join co-operatives (and give time and money etc.)
- Join community groups (these don't even have to be political)
- Support local, independent media and good freelance journalists
- Spread the word about all of the above
I've ordered these roughly by how effective they're likely to be. Fair warning, none of the above will instantly fix the problem and I grant that some of them probably seem pretty weak sauce in the face of fascism, but the more people do them, the weaker the fascists will get.