I think the "How do I ask a good question?" Help Center page could use some work. Part of it is wrong, some of it could use more info, and some of it could be expanded. Let's go through what's there, and then let's brainstorm some ideas for improving it!
I'm personally okay with the existing verbiage for the most part. It might be nice to have some XY Problem description, but I'm not sure this applies to non-technical SE sites as much as those with technical Q&A. So that could be problematic, since the same text is shared across multiple sites.
But I would add that Stack Overflow's customized How to Ask page has some very useful elements that I hope could improve the question quality on all SE sites (with the understanding that I haven't studied every SE site).
I've edited the following slightly from the SO version so that it applies to "non-technical" sites as well. I would propose the following be added to the site-wide SE,
Proof-read before posting!
Now that you're ready to ask your question, take a deep breath and read through it from start to finish. Pretend you're seeing your own question for the first time. Does it make sense? Add any details you may have missed and read through it again. Now is a good time to make sure that your title still describes the question!
Post the question and respond to feedback
After you post, leave the question open in your browser for a bit and see if anyone comments. If you missed an obvious piece of information, be ready to respond by editing your question to include it. If someone posts an answer, be ready to provide feedback if applicable!
Here's what I think should be changed:
If you ask a vague question, you'll get a vague answer. But if you give us details and context, we can provide a useful answer.
Incorrect. Vague questions that can't be fully answered without more details should (and hopefully will) be closed as "Needs Details or Clarity", perhaps with a (polite) comment explaining what else is needed. Vague, incomplete answers aren't the correct action for insufficient detail in a question. Either the question is specific enough for a good answer, or it isn't. But let's not encourage posting incomplete answers to incomplete questions.
Make it relevant to others
We like to help as many people at a time as we can. Make it clear how your question is relevant to more people than just you, and more of us will be interested in your question and willing to look into it.
This is true, but mostly unhelpful. To me and most active SE users, this makes sense. But think about it from the perspective of a first-time question asker who knows nothing about the SE model - "Why should I care about it being useful to others, I just want an answer to my problem". If we're going to say that (which we absolutely should IMO), let's include a few ways to do that. Not exactly sure how, but I don't like this wording. I realize it says "... and more of us will be interested in your question and willing to look into it", but most new users will have stopped reading far before that.
Therefore, I think in addition to having sections, we should make sure that there are in the order of importance, and phrase it in a way that they are more likely to care about. Here's one idea:
To increase your chances of getting a good solution, try to ... so that more people will look at it. This also makes it useful to others, which is better for everyone.
Of course, other ways to word it could work better
Keep an open mind
The answer to your question may not always be the one you wanted, but that doesn't mean it is wrong. A conclusive answer isn't always possible. When in doubt, ask people to cite their sources, or to explain how/where they learned something. Even if we don't agree with you, or tell you exactly what you wanted to hear, remember: we're just trying to help.
Yes, frame challenges (this) sometimes happen, and being open-minded is important. Although, frame challenges tend to happen when the OP has an XY Problem, so IMO we should explain (or link to?) the XY Problem.