Sometimes I feel uncomfortable to say "How do you spell xxx ?". It sounds like asking his or her own way of spelling a word implicating that I am not necessarily expecting the correct answer. Is "How do you ... ?" a polite question to ask the right way to do things ?
closed as general reference by MetaEd♦, Kristina Lopez, choster, cornbread ninja 麵包忍者, tchrist♦ Jun 15 '13 at 14:29
This question is too basic; it can be definitively and permanently answered by a single link to a standard internet reference source designed specifically to find that type of information. If this question can be reworded to fit the rules in the help center, please edit the question.
The pronoun does not necessarily refer to the second person alone or (contextually, the first person here); you has another meaning!
2. Also one, refers to an unspecified person or people in general you can't tell the boys from the girls (http://www.thefreedictionary.com/you)
Usage: You is also used to imply 'a person in general,' 'one,' ...
You should be already familiar with this usage, though not aware of it. a tiny animal you can't even see. (ibid.)
I think that "How do you do X..." is almost universally understood as a less formal version of "How does one do X..." so I think your question is fine.
Responding to the broader question you put, it wouldn't be polite to ask "How do you spell xxx?" before a polite introduction. Generally, this would include a greeting and some small talk. The switch to the question can be smoothed by a hedge such as "Can I ask you a question - ...".
Some might say that "May I ask you, ..." is preferable here, but that would sound stuffy in casual conversation. And while "How does one spell xxx ?" is probably logically preferable for the reason you suggest, it sounds ridiculously formal. "How do you spell xxx ?" is preferable by far - the 'you' is not stressed, in fact, hardly pronounced ("How d'yə spell xxx?" - cf "How d'yə do?") - to show that the 'you' in this case means 'people in general'.
"How does one spell..." is infinitely better than "how do I..." or "how do you..." because spelling is never open to interpretation!
If that is too formal, one could ask, "What is the correct spelling of..."