Much of the work that effective altruists do is augmented by ties to the industries to which they relate. Global poverty researchers can often further their impact when associated with relevant university departments, think tanks, or government agencies. Animal welfare advocates have a whole network outside the one in the EA community, whose knowledge and expertise can be a great stepping stone for further work. Advocates for greater thoughtfulness and generosity in giving can appeal to religious and secular groups alike, particularly those who are likely to take to EA concepts. Existential risk mitigators could benefit from joining professional groups in the fields of defense, intelligence, and AI research.
This is a bit like bringing EA to your workplace; in this case, rather than just discussing the subject with colleagues, you're trying to spread an EA mindset through your field -- and bring ideas from that field back to the EA community.
If you have close ties to a community that has relevant components to EA or believe that you could create those ties, we encourage you to do so, and help the rest of the community learn from your experience. You can do a write-up of the field, highlighting its relevance to EA goals, and publish your findings to the EA Forum.