Organizing the contents - headings, paragraphs, lists, etc

The tags for expressing major structural features, so-called block level tags, are the following:

• headings of different levels: H1, H2, H3, H4, H5, H6
• paragraph level tags:
  • normal paragraph: P
  • quotation presented as separate paragraph: BLOCKQUOTE
  • author's address information as separate paragraph: ADDRESS
  • preformatted text to be displayed as such, preserving layout (lines, blanks): PRE
• lists:
  • normal unordered list: UL, LI
  • compact list of one-line items: MENU, LI
  • list of small items: DIR, LI
  • ordered list: OL, LI
  • definition list (labelled list): DL, DT, DD
• tables: TABLE, CAPTION, TR, TH, TD
• division of document into parts which may have their own layout properties (such as centering): DIV, CENTER
• change of topic: HR
• fill-out forms: FORM, ISINDEX.

A recommendable approach, which may need adjustments to fit your local recommendations, is the following:

1. Write a descriptive heading for the entire document and use H1 element with ALIGN=CENTER attribute for it.
2. Divide the document into major parts (sections), write suitable titles for them, using H1 with ALIGN=LEFT. In this and further divisions, try to avoid having more than seven parts.
3. If necessary, divide each major part into smaller parts with H2 headings, and if needed divide each of these subsections into subsubsections with H3 headings. Avoid using H4 headings and especially H5 and H6 headings, both because they are often rendered with a very small font and because more than three levels of structure tends to make the document hard to read. (If you still feel tempted to use H4, consider dividing the entire document into smaller documents.)
4. If you have a section with, say, H2 heading and containing H3 headings, avoid inserting text between the H2 heading and the first H3 heading. Such "homeless" text can be acceptable if it only contains very short notes such as general orientation, some remarks about the section, or a motto. Long homeless texts confuse the reader who does not see your good intentions; therefore, use a subsection with a heading of the appropriate level and with text like Introductory remarks, Generalities or Summary.
5. Divide the smallest parts of the above-mentioned structure into paragraphs or paragraph-like blocks (namely lists or tables). as described below. Notice that in HTML you must explicitly indicate paragraph division by HTML elements; leaving just an empty line does not cause a paragraph break.
6. Within paragraphs, use text level markup, normally phrase markup, to distinguish special text segments from normal text, e.g. to indicate quotations of computer output or to emphasize key words.
7. Add links and, if applicable, images or other illustrations.

• For normal text paragraphs, use the P element.
• However, if the text of the entire paragraph is literally quoted from some source, use the BLOCKQUOTE element or, if it is program code, computer output or some other text that shall be presented exactly honoring the division into lines, use the PRE element. In the latter case, if monospaced font is not suitable (e.g. the text is a poem), use BLOCKQUOTE and append a BR element to each line.
• As a special case, if the paragraph is intended for providing information about the author (that's you), use the ADDRESS element.
• For itemized information, which logically consists of separate cases or items, use various elements as follows:
  • For list of items where the order is not significant, such as a list of ingredients in a recipe, use the UL element, or the MENU element (for a list of rather small items), or the DIR element (for a large list of small items, suitable for presentation in multi-column format). However, since most browsers do not present MENU and DIR in the manner suggested in the specifications but as identical to UL, you may wish to consider other possibilities as well, such as using tables to represent menus. - Notice that e.g. in an alphabetical list the order is usually not significant in the relevant sense; if the order is so explicit, there is hardly any need to make it more explicit e.g. by using numbering.
  • For list of items where the order is significant and this significance needs to be made explicit, such as a sequence of instructions to be obeyed in that particular order, use the OL element.
  • For a list of items with short titles or tags, such as a list of definitions for terms or abbreviations, use the DL element. However, you may like to consider using a TABLE element to present a definition list as an alternative.
  Notice that in a typical implementation MENU and DIR elements are rendered similar to UL elements. Moreover, DL element rendering can be awkward, too. Please browse a separate file Examples of various list elements in HTML to see what renderings of lists look like in your implementation. - The UL, MENU, DIR, OL, and DL elements are "plain lists" with no such structural feature as the CAPTION in a TABLE element. It is usually desirable to have some sort of heading or explanation before the list, but from the HTML viewpoint it is a separate paragraph.
• For tabular information, normally use the TABLE element, but consider the possibilities provided by PRE and DL elements, which may be suitable in special cases.

List can be nested in the sense that an item in a list, i.e. an LI (or DD) element, may in turn contain a list element.

Notice that the basic paragraph element P is not nestable, i.e. you cannot have P elements within a P element to create subparagraphs. However, the various list elements effectively provide an itemization structure which essentially corresponds to subparagraph division. Moreover, the list elements are nestable.