Some good comments, which partially cover your questions. I'll try to cover them methodically here.
What makes a good Cross Validated question?
In this order, or similar:
- A clear introductory statement of what you are trying to achieve: what point you are trying to get across?
- Why are you doing it? Homework? Part of your job? Self-education?
- A brief, clear description of the data you have. Describe each variable. Ideally, provide a couple of rows of data, so people can see the format it's in. Say what programming language you're using.
- If, and only if, you can see a good way to generalise the question (other projects you plan on doing, using similar concepts or something), then put it out there. Otherwise, just assume that the people who come after you are not stupid and they will be able to generalise it themselves. Everyone is used to doing this, as this is the most common way we learn: by example.
- Clarification of your experience (see next section), but only if you feel it's necessary.
- A clear statement of your question or questions. You are best off sticking to one clear statement of your core question, rather than multiple questions or multiple formulations of the same question. Those questions may seem related to you but there's a chance they won't seem so to others. You can always post follow-up questions to clarify certain aspects. Doing so and linking back to the original question will make it easier for people to pick up what you're trying to communicate. If you think that you have side-questions that aren't suitable as separate posts, then feel free to add them, but make sure to indicate that they are less important. One way you could do this is to make your main question statement bold.
- Re-read your question and remove all guff. You don't need to apologise for your perceived inadequacies nor do you need to thank people for anything. Anything that doesn't add relevant information is only detracting from your communication effectiveness.
There are few stylistic restrictions: write naturally and use a language familiar to you rather than one you think statisticians might speak. Work to make your question stand by itself and be understood by everyone. In particular:
Define or explain any technical terms and mathematical symbols you use. Do not assume everyone uses your terms in the same way (statistics applies to a huge variety of disciplines) nor that a given symbol invariably stands for one thing.
Explicitly write out, in full, the first occurrence of any abbreviation or acronym.
Strive for standard appropriate English usage, grammar, and spelling. It's easy: pay attention to the automatic spell-checker markup when you're writing. You need not be as formal as, say, an academic journal, but don't be too chatty either. Avoid abbreviations or calculated misspellings used in texting (e.g. u or U for you).
Use the highlighting tools (found immediately above the textbox) to create headers, emphasize text, and inset code and quotations.
Format mathematical expressions using $\TeX$ enclosed between dollar signs $\$$ (or double dollar signs $\$\$$ for centered expressions).
Some things to avoid:
Do not beg for help. We know you would like a great answer as soon as possible.
Do not include identifying information such as your name or e-mail address--we will remove it if it appears, anyway. You can place those into your user profile for all to see.
Do not solicit offline or private responses: questions and answers are posted here for everyone. We are more than (just) a Q&A site!
Clarifying your experience
Take your lesson here from the master, Donald Rumsfeld:
- Known knowns: State any relevant information that you already understand, as concisely as possible. Say why it's relevant. Feel free to say something about how experienced you are in stats.
- Known unknowns: If you're aware of certain methodologies, theorems, tools, etc. that you think you might need, but are not familiar or comfortable with, say so, and say why you think they're relevant. People can pull you up here, if necessary.
- Unknown unknowns: You don't know about these, so don't fret about them. If someone brings some up, then you can add them to the previous category.
You can't do much better than that. Don't labour over it, and keep it as short as possible, or people will get bored and leave.
If someone mentions something for which you require clarification, ask in the comments. If it changes the question substantially and answers have already appeared, you may be better off abandoning the question (out of respect for the material already posted) and starting again with your new information. Otherwise, you can just edit the question.
Misunderstandings, in my experience, occur because of lack of context. Statistical concepts are hard to communicate clearly and it's easy for someone reading your question to completely miss what you're trying to get at. A good way to add context is to provide a solid example.
If you don't understand the relevance of a comment, say so, and state clearly why you think it is not relevant, so that the answerer/commenter can get a better handle on where you're coming from. This will allow them to give you more targeted context for their comment.
Do I need to be a statistician?
No. Certainly not. The site is aimed at people interested in statistics, practice or theory. You just need to be open to learning.
It also helps to be a good communicator and to know your audience. This is difficult to learn in any situation, let alone one in which most conversations are unintelligible due to lack of experience (I've been hanging around here for almost a year, and I still don't know WTF most people are talking about;)). Remember that people here come from all different backgrounds (different languages, different areas of study, different levels of experience with stats) and you can't assume that anyone knows what you're talking about.
The great thing about StackExchange is that it's really hard to be a troll here, so no-one bothers much. If it looks like someone's being narky, it's probably best to assume that they're just not communicating well, and ask for clarification. Above all, please be patient and give everyone the benefit of the doubt: we're here to help.