The rationalist tumblr sphere helped me a lot. It's a lot more approachable for newcomers than this site is and has a very low barrier for making low-effort, high emotion posts, which is something I could totally use assistance on at the time. It also helped that I could see rationalist practices and the results in (more-or-less) real time, which were highly available examples (I've always learned better with good, tangible examples) and showed me that rationality could be practised by "real" people, rather than mythical figures like Jeffreyssai, the Defence Professor or Eliezer Yudkowsky.

Yudkowsky's fiction also helped because it provided easy-to-read content that teaches the basics. For the same reasons, I Shall Wear Midnight (by Terry Pratchett) was useful