1) Be specific. Well-defined problems are easier to get one's teeth into and will attract more helpful responses. If you don't know yet and just want suggestions, be specific about what sounds you're wanting to achieve. It's very helpful if you're specific in the thread title as well. A title like "wirng idea" or "help?" might get passed by, whereas something like "series blend pot for strat?" will catch people's eye and is easier to find again.
2) Stick around. Don't leave your thread to twist in the wind. If someone gets back to you, asking for clarification, respond before they forget about your question.
3) Make an attempt to understand what's being said and be ready to come up with an alternate idea if your first idea turns out to be unfeasible.