There's two items that should be followed much more often:
Always use heading levels in order, with one heading level 1 at the top of the document, and if necessary several level 2 headings, and then if necessary several level 3 headings under each level 2 heading. If you don't like the way heading level 2 is formatted, fix it on your client, don't just skip to heading level 3. -- http://www.w3.org/Provider/Style/All.html
Don't refer in your text to facets of particular browsers. Asking someone to "click here" won't make sense without a mouse, just as asking someone to "select a link by number" will betray the fact that you were using the line mode browser. Just leave a link. The instructions get boring as the user will normally know how to select a link. -- http://www.w3.org/Provider/Style/All.html
Always use heading levels in order, with one heading level 1 at the top of the document, and if necessary several level 2 headings, and then if necessary several level 3 headings under each level 2 heading. If you don't like the way heading level 2 is formatted, fix it on your client, don't just skip to heading level 3. -- http://www.w3.org/Provider/Style/All.html
Don't refer in your text to facets of particular browsers. Asking someone to "click here" won't make sense without a mouse, just as asking someone to "select a link by number" will betray the fact that you were using the line mode browser. Just leave a link. The instructions get boring as the user will normally know how to select a link. -- http://www.w3.org/Provider/Style/All.html