Post Quality
Be sure your forum posts actually contribute to the topic being discussed.
Posts that contain solely "Lol", "This", GIF/image replies, or other short remarks are usually better suited for chatrooms than forum discussions.
Keep your posts coherent and try your best to use good grammar.
Do not create threads and posts solely to advertise your blog, forum, Tumblr, YouTube, or website. Instead, use your signature to share these websites, but be sure to follow the signature rules.
Do not post in an old thread if the topic is no longer relevant. This is known as bumping a thread.