Sorry, I forgot
<facetious></facetious> and
<sarcasm></sarcasm> don't always work here. ;-)
Seriously, though, is there some concern that an entire page of "Where should I post X?". "How do I compose an effective node title?", "How do I post a question effectively?", "Markup in the Monatstery", "Posts may use any of the Perl Monks Approved HTML tags: (followed by a paragraph of tags)", "If you think you're going to use <pre> tags — don't! Use <code> tags instead! This applies to data as well as code.", "Outside of code tags, you may need to use entities for some characters: (followed by the 5 most-used characters that need to be entities)" and " See Writeup Formatting Tips and other pages linked from there for more info." in addition to the blurb above the text entry box just makes it all blend together?
One or two very simple and clear directives would be less likely to get lost in the clutter. Pointing people to read an "etiquette of posting" and giving the absolute most basic information, such as the "Your (PerlMonks-approved) HTML-formatted text:" I personally believe would make it more likely people would follow that etiquette. Trying to teach it all at every node posting does make it available to people more directly, but I think it both diminishes the impact visually and dilutes the psychological impact of the individual points.