Taboo "rationalist". That is, don't make it sound like this is a group or ideology anyone is joining (because, done right, it isn't.)

Discuss, as appropriate, cognitive biases and specific techniques. E.g. planning fallacy, "I notice I am confused", "what do you think you know and why do you think you know it?", confirmation bias, etc.

Tell friends about cool books you've read like HPMoR, Thinking Fast and Slow, Predictably Irrational, Getting Things Done, and so forth. If possible read these books in paper (not ebooks) where your friends can see what you're reading and ask you about them.