**I try to always answer in 3 paragraphs whenever possible.**  Less is often too little for a substantive answer, and more becomes less and less likely for people to read.  The first paragraph should always be the most direct answer to the main question in the original post, as asked, with a minimum of editorializing.  It should generally cite a [reputable source](https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources), with a link, but also recapitulate the information that is linked.  Sometimes I will boldface a key idea, no more than one per paragraph at the most.  The most important thing is to remember that this is audience-oriented, persuasive/informative writing, it must be simultaneously substantive, useful and compelling.

My second paragraph is a place to expand on my answer, or to answer the question that I really think should have been asked, instead of the one that actually was asked.  Even when doing so, however, I think it's important to treat every question as legitimate, as reasonable and as asked in good faith (otherwise you shouldn't be answering it).  **It's also important to not make the querent feel stupid or ignorant for not having your level of knowledge.**

Does it even make sense to ask for "the" way to write SE answers, since they are all so different?  I do think there are some generally useful structures that aren't content-area specific.  For example, if I want to criticize the question itself or offer original or controversial ideas, I reserve those for the last paragraph.  I've found that the very same things that enrage people, or cause them to dismiss an answer when contained in the first paragraph, are often accepted without comment in the last paragraph, especially if they are clearly labeled as "original" or "editorial."  **It's worth noting that the exact same conceptual content can garner very different reactions, depending on how it is presented, and in what order.**  Finally, I nearly always revise frequently, and to do my best to accept all critiques in the comments non-defensively, and to respond to them productively (generally through revisions).