Make sure it’s obvious what you’re trying to get out of the question. Too many “questions” are actually just statements: when I do X, something goes wrong.
Well, what did you expect it to do? What are you trying to accomplish? What have you already tried? What happened in those attempts? Be detailed: in particular, if something didn’t work, don’t just state that: tell us how it failed. If it threw an exception, what was the exception? (Don’t just give the type – give the error message and say which line threw it. If there’s a nested exception, post that too.)
If at all possible, write a sort of “executive summary” at the start of your question, followed by a more detailed description. Remember that on the list of questions, the first few sentences will appear as a snippet. If you can get a sense of the question across in that snippet, you’re more likely to attract views from people who can answer the question.
One trap that many posters fall into is to ask how to achieve some “small” aim, but never say what the larger aim is. Often the smaller aim is either impossible or rarely a good idea – instead, a different approach is needed. Again, if you provide more context when writing your problem statement, we can suggest better designs. It’s fine to specify how you’re currently trying to solve your bigger problem, of course – that’s likely to be necessary detail – but include the bigger goal too.