Discuss, think and learn with a friendlier atmosphere. Avoid tangential, meta, personal or harsh criticism.
In Friendly, posters choose what topics they want to discuss. Suppose someone posts a physics question. Don’t reply about how their question reveals that they’re dishonest, emotional or overreaching. Don’t criticize them for ending the discussion early or for not doing Paths Forward. Those would be topic changes away from their intended topic (physics). If you do want replies like that, put your topic in Unbounded.
Any thoughtful topics can be fine except politics. Good topics include: philosophy, rationality, learning, thinking methodology, discussion organization, morality, memes, science, history, writing, grammar, math, evolution, programming, statistics, economics, political philosophy, psychology, psychiatry, parenting, education, relationships, atheism, skepticism, business, sales, marketing, art, design, social dynamics, culture, and decisions people face in their lives.
News can only be shared in Friendly if you focus more on philosophy than on the news. E.g. focus on critical thinking, analysis, or trying to deal with it rationally. Your post should be more timeless than time-sensitive. And avoid political controversies in Friendly.