Use meaningful and descriptive titles
On mailing lists, newsgroups, or forums, headlines of about 50 words or less are a great opportunity to grab the attention of seasoned professionals. Don't waste it by droning on about Help', Knee-jerking', Urgent' (not to mention Help ！！！！ ` such off-putting words will be reflexively ignored with such headlines) to squander this opportunity. Don't presume to impress us with your level of pain, but rather ask the question in this point in space using an extremely simple and concise description.
The title should describe the problem, not the emotion
A good example of a headline is a goal-difference' description, which is what many technical support organizations do. In the Objective' section, indicate which thing or set of things is the problem, and in the `Difference' section describe the inconsistency with the desired behavior.
Stupid question: help! My laptop doesn't display properly anymore!
Clever problem: X.org 6.8.1's mouse pointer gets distorted with a certain brand of graphics card MV1005 chipset.
Smarter problem: Mouse pointer of X.org 6.8.1, in the environment of a certain brand of graphics card MV1005 chipset - distorts.
The process of preparing a `goal-difference' type description helps you to organize your thinking about the problem in detail. What was affected? Is it just the mouse pointer or some other graphic? Only in version X of X.org? Or only in version 6.8.1? Is it for a particular graphics chipset? Or just one of the MV1005 models? A hacker can instantly understand your environment and the problem you're having with just a glance.
Good title also makes it easier for later searches
In a nutshell, imagine that you are searching through an archived Thread index that shows only the title. Having your title better reflect the question will allow the next person searching for a similar question to follow the thread without having to ask the same question again.
Maintain the title when replying as well
If you're going to ask a question in a reply, remember to change the title of the content to make it clear that you're asking a question; a title that looks like Re: Testing or Re: New Bug is hard to take seriously. Also, quoting and abbreviating from the previous post can give clues to new readers, without compromising coherence.
For discussion strings, don't just hit reply to start a whole new discussion string; this will limit your audience. Because some mail-reading programs, such as mutt, allow users to sort by discussion strings and hide messages by collapsing discussion strings, people who do this will never see the messages you send.
It is not enough to change the headers. mutt and some other mail readers will also check for other information than the headers in order to assign a discussion string to the message. So it is better to send a completely new message.
Differences in web forums
On web forums, a good way to ask a question is slightly different, because the discussion string is so closely tied to a specific message, and the contents are usually not visible outside the string, that it is acceptable to ask a question by replying rather than changing the title. Not all forums allow split titles in replies, and basically no one will read them if they do. However, asking questions by replying to them is ambiguous practice in and of itself, as they will only be read by people who are viewing that title. So unless you only want to ask questions among the people currently active in that discussion string, it's better to start a separate thread.
A reliable criterion for determining this is whether an unfamiliar reader can tell what anomaly you've encountered in what setting when reading only the headline. If they can't, the headline isn't good enough.