I am a new user of tex.stackexchange.com and probably this could be a stupid question, but is there any information about how to pose good questions and make good answers? I think it could be useful for new users. If possible can you enumerate 2 or 3 topics to read for each case:
Here is a collection of ideas, taken from comments and the FAQ for Stack Exchange sites:
Search first
We typically come to a Q&A to get an answer. Immediately. However, there is a bounty of knowledge already present on this site. Search for it using the best ninja skills you have possible. Only then post a question. For not-so-new users, the chat room is also a good place to hash out ideas about questions.
Duplication is fine if it turns out that the problem can be approached from different angles. Your question (even though it is a duplicate) may be the landing place for others searching for similar solutions. Questions marked as a duplicate will have their duplicate targets clearly listed:
Include a minimal working example (MWE) so that the actual problem can be replicated by the community.
Since we're not sitting next to you and a post is the only way you can communicate the problem, a MWE is like a picture... and worth a thousand words. Remember to keep it minimal. How do you know when something is minimal or not? Remove stuff until the problem is not reproducible.
Write a descriptive (yet short) title
A title saying "How do I fix this error" doesn't help any future visitors who search this site. Like any search engine, question titles are included in the search results, together with snippets of text/code:
So, while "How do I fix this error" may mean something to you at the time of posting the question, you should...
...have the bigger picture in mind - the community.
The community is here to help you, so try to put yourself in their shoes when you post. Can they readily reproduce my problem? Have I given clear instruction as to what I'm after? Do I have an XY problem?
Include references and pictures
A reference to a different question will show that you've done some research or tried other avenues (perhaps you'd like to ask a follow-up question). Pictures of the output (expected or actual) give most members an immediate take on what's going on. Again, a picture is worth more than a bunch of sentences. We have guidelines on how to include images in posts - new users should follow the same procedure but remove the preceding ! (markdown inserted to denote a picture). Janitors will be able to rectify this and fully embed the image.
Mark your code properly
There's an FAQ on how to mark your code using markdown. It improves readability.
Tag like a boss
We have many house-keepers in this community, all of whom try to keep up with ordering things on this site. Tags are important for that. And, as you may have noticed, searching based on tags (using [<tag>]) can help narrow your searching to find what you're looking for.
Be specific
Think of the answer you require when formatting the question. As a reference, see How to ask a specific question without in the risk of "too localized"?.
Search first
Yes, some questions are duplicates. If they're found, flag a question or directly close it as a duplicate.
Don't post link-only answers.
These are better-suited as a comment, since it defers reputation to the intended posts (not yourself). Sure, link to other posts that support or confirm some of your suggestions/usages, but keep in mind that your answer should add value to the community.
Code-only answers are not that awesome.
New users sometimes have a lacking ability to interpret code-only answers. It helps if there are explanatory discussions around why certain things were done.
tex.
observe and learnfrom the pattern of Good Q & A for a few days on TeX.SX. Once in a while everyone fails to ask a good Q, but don't resist to ask or answer even stupid Questions. Over time it may turn Good. BTW for eg: see this User's Q & A tex.stackexchange.com/users/19356/?tab=questions to get some idea.