Search First
The best forums have search engines that can browse an archive of posts by keyword. Use this tool before burdening your new web friends with a question they may have already answered. Also, read the most recent text to see if you should start a new thread or just continue with a pre-existing one.

Categorize
Many forums are subdivided into a variety of topics. Make sure that you post your question or comment (just once to avoid verbal clutter) in the correct place.

Subject-ivity
Your post will carry a subject title. Try to be succinct and descriptive with the title, so that your neighbors will know immediately if the post pertains to them. Use of capital letters and excessive punctuation in subject headings is considered "shouting" and is generally frowned upon. So instead of logging onto a fitness forum and writing, "Need Arms Like Cantaloupes" try posting "Anybody know any good bicep exercises?"