Got this from http://www.wikihow.com/Ask-a-Question-Intelligently:

1. Define exactly what it is you want to know. This involves categorizing all the concepts in your head. Once you have the concept you are unsure of clearly in your head, then you can begin. Don’t ask a question just for the sake of it.
2. Never ask a question in an aggressive manner that indicates you are only asking the question to prove to the other person that you are right and they are wrong, unless they are wrong and refuse to admit it. Ask because you are genuinely interested.
3. Start off with something simple that lets them know that you are about to state your opinion, but realise it is not complete and you are hoping they can fill in some gaps.
4. Lay your concepts/ideas and assumptions on the table taking care to make sure that the other person is fully aware of exactly what your current thinking is, and why you think it.
5. Pleasantly ask for the gap in your knowledge to be filled, and if appropriate, ask them how they know this and what the general trend is that would short cut path to that knowledge. i.e. no use in asking “is that alive? is that alive?” to everything you see, when the general trend is “if it grows and/or moves independently, then it is. otherwise, you can take it as a given that it is not.”
6. Thank the person. Try and return the favor sometime.

Tips:

• Example: “well, up to now, i’ve always thought that classical music was awful music and not worth listening to. Maybe it’s because all my friends hated it. But if musicians and educated men and women enjoy it, there must be something to it. I know you like it, so can you tell me what there is to appreciate?”
• Incorporate the audience into the question. Invite them in with phrases such as- “did you think about..” or “Have you considered this question…”
• Try and read more so you have substance to what you are actually saying.
• Don’t use huge words. They’ll make you sound pretentious. Just tap into your intellectual but friendly side, and don’t worry too much about coming off as brilliant.

Warning:

Watch out for getting aggressive at the response you get if you don’t like the answers you get. If you’re not willing to receive any and all answers, don’t ask the question. Sometimes a person can answer aggressively to your innocent query. Don’t fret. They just think the question was beneath them, and that you are stupid to ask it. You’re not. They are just bitter and have forgotten what it’s like to search for answers. Basically they think they know everything. You know you don’t. You’re the tortoise. They are the hare.