<p>By explaining what more you're looking for than you'd get from reading the relevant Wikipedia article, a textbook, or whatever a couple of minutes' Googling turns up. Bringing up some point of confusion or a difficulty in application presents people with a fun challenge (whether that's to explain something, or to work it out for themselves &amp; then explain it) rather than a boring request for information readily available elsewhere.</p>

<p>Of course questions that come down to "explain $X$ to me" sometimes get very good, original, answers&mdash;like @Glen_b I think that's just luck.</p>
