I thought I would write a meta post giving my advice for improving titles. (Feel free to add your own advice too.)
I've been making substantial edits to question titles on Islam.SE. Most of the time, I just track down the actual question the user asks in their post, and rephrase the title to match that as closely as possible.
Why are titles important?
Question titles are the most visible aspect of the home page.
The title of a question is the first thing people see, and we decide whether or not to read the post based on the title.
Searching this site, either through the site's search feature or through search engines, is facilitated by functional titles. Indeed, most users find Islam.SE through search engines.
Closing questions as duplicates, and ensuring one does not author duplicates, is easier when we know what questions are about without having to open them.
The home page is a list of titles. We should make it look professional and attractive to experts. We're competing with Quora (whose titles are readable) and QA.Islam.com (whose titles are almost useless).
What's the problem?
How many thousands of different questions would fit equally well under the following heading?
What differentiates it from How can I determine if this hadith is authentic? or Can anyone verify this hadith? or Hadith about the Prophet? (I now changed it to: Is the hadith "true scholars are those who speak... the truth against tyrant rulers" sahih?.)