Honestly building communism means being sociable. People adopt the beliefs of their peer group. So we can just absorb people like a big red amoeba if we just keep making more friends and inserting them into our social group. Getting some cultural consensus and influencing the base consensus assumptions people have about reality (as neo-liberal ideas became cultural consensus for awhile) so go to that party, join that book club, go for drinks with your coworkers, make memes, and build communism.
You can get non commies to repeat commie ideas if they hear them often enough, and once you get those base assumptions (like the labor theory of value) in there it’s a hop skip and a jump to waving a red flag and singing the internationale.
Also humor is a great tool because it gets shared for its amusement value even by people who don’t necessarily agree with the politics, and is a great way of slipping ideas in under the radar. Also it challenges one of the biggest shitty assumptions about communists (which is that were dour and humorless and no fun)
Make an effort to be nice, welcoming and non-prickly. Invite people to board game nights (with a bunch of communists), invite them out for drinks (with a bunch of communists), to house parties (with a bunch of communists), and dinner parties (with a bunch of communists) and don’t waste time having insular minor theoretical arguments with weird Trot sects, just out organize them.
Thoughts From The Peacock Angel 