Since effective altruism is still a nascent field, lots of existing information has yet to be published. If there's some new topic you'd like to learn about and/or share with others, interview a relevant expert and write up the interview. They might be able to tell you about a field of knowledge, a problem area, or their experience.
Rob Wiblin of the 80,000 Hours Podcast and Julia Galef of the Rationally Speaking Podcast conduct such interviews, but there are only so many topics they can cover. You can help others become exposed to important but little-known ideas by following their lead.
To get started, check out Nick Beckstead's advice on doing prioritization research in this manner. Then, to get a sense of how to do this well, check out examples of different styles of expert interviews to determine your format. Others have covered, for example, global poverty interventions, earnings maximization, entrepreneurship, and personal success. Once you've written up your interview, ask the interviewee to review the piece then share your findings on the EA Forum. (h/t Richard Batty)