Just some pointers off the top of my head:
- Use a descriptive title (when it comes to titles, it is more important to be descriptive than polite)
- Immediately in the post: describe what is not working in one sentence
- Give a quick recap of what was done, in list form, if possible
- Provide relevant specifications, e.g.: OS version, browser version, motherboard, graphics card, etc. (preferably with links)
- Provide relevant references, e.g.: literature that you looked up on the Internet, your research, etc. (again, preferably with links)
- Provide relevant history, e.g.: your story, rationale, considerations, etc. -- whilst it is tempting to start with your story, it is often the least relevant
- Save the thank yous, closing remarks, etc. for the end of the post
Yes, the order of this list matters.
Yes, it is important to use proper punctuations and be polite. The grammar does not have to be impeccable. But it is good to know that efforts were made to convey information as clearly as possible.
And yes, it helps to keep things in the same thread.
p.s. I was reluctant to make this post, but it seems like a good reminder to some. Ultimately I hope everyone get the information they come to look for, so I hope this helps.