A Question is composed of three distinct parts:
By far the most important is the body of your question because this is where you pose the all important single question that you would like answered. It is the quality of your question body that engages or loses the attention of potential answerers.
You are provided with plenty of space and formatting tools here to assist you to present any technical background that potential answerers may need to understand your question.
Start by mentioning the single GIS software (and version) that you are using and wish to ask about, or explain that you are asking about a GIS principle or algorithm instead. This saves potential answerers having to try and guess, or to ask, all of which may slow down or prevent an answer to your question.
The question body may well be the only part that potential answerers read and re-read after glancing at the title, so be sure to read and re-read it yourself, and to make ongoing edits to improve it as clarifications are sought by others via comments. You cannot assume that a potential answerer has read any of your previous questions, answers or comments so be sure to include all relevant details in the body so that it can standalone.
Once written, a good cross-check on your question's body is whether it contains a single question mark? If that is the case, then what you are asking is clearly indicated. If you find yourself wanting to place more than one question mark in the body, then questions other than the most important one to you can always be researched/asked separately.
A question that ends with "Any ideas?" or one that asks for examples to be provided (i.e. to make a list) suggests that what you are asking may be too broad. One that asks for step-by-step instructions will be too broad because we do not offer a tutorial writing service. Try always to ask a specific question.
If you are asking a coding question I strongly recommend reviewing How to create a Minimal, Complete, and Verifiable example so that what you include is just a code snippet that works up until where you are stuck. GIS Stack Exchange does not offer a code debugging/writing/reviewing service but we are generally happy to try to help you debug your code snippets.
If you have not already taken this site's 2-minute Tour then be aware that it says:
This site is all about getting answers. It's not a discussion forum.
There's no chit-chat.
By "no chit-chat" we mean that words and phrases that are superfluous to the actual question being asked (or answers to it) like "Hi", "Greetings all", "Thanks", "Please", "Much appreciated", "Tearing my hair out", "Hope that helps", "Cheers", etc should not be included to try and connect socially with, or convey a sense of urgency to, potential answerers.
The quality of your question should be all that is needed to entice one of our many volunteers to answer it, and chit-chat (no matter how polite) will usually be removed. If you find yourself writing something that you might see in a personal communication but would not expect to see on a Wikipedia page, then you may be starting to bloat our focused Q&A with chit-chat.
The title is best written after the body of the question because it is there to summarise what is in the body. As a result it should not introduce any new terms or information not covered in the body. By making this as succinct and accurately descriptive of the body as possible you are likely to attract more potential answers than if you hastily pen something like "Help! GIS not working!!???".
My preference is for the title to always end in a question mark because that acts as a constant reminder that this site is about finding answers to questions. I recommend reviewing this answer to a Meta SE question for some thoughts on what makes a good title.
These help the people who are willing to try and help you quickly find the subset of questions in which they have skills instead of having to open many in which they do not.
I prefer that there is one tag used for the main GIS product that you are using, and often another for the version you are using of that product. This still gives you scope to apply 3-4 more tags that reflect the significant keywords that are likely to help group your question with others that are somewhat similar.
Do not worry if you get tags "wrong" - they are always quick and easy to fix as incoming questions are triaged as long as the information is in your question body.
What about Comments?
Comments are attached to, but do not form part of, your Question.
Their main purpose is to help you edit to improve your Question by requesting clarifications wherever potential answerers are unsure of what you are doing, using or asking.
Imagine the pleasure of a potential answerer reading just your Question body and thinking immediately "I know the answer to that", and answering it, versus reading a trail of back and forth comments between asker and commenters and thinking "does it mean this" or "does it mean that", and eventually "now I understand" or maybe not, or not bothering to read the comments and just moving on to the next Question.
What about Answers?
Answers should never be written in questions. We have a separate area for answers, and self-answering in that area is encouraged.