Other tools
Sidebars
Sidebars and boxes allow you to present ancillary information such as, for example, details or case studies. They also allow you to present information that is just far enough away from the main theme to create confusion if integrated in the flow of the text. All boxed materials must clearly link to the main text but not be an essential part of it.
Sidebars can also be used to summarise the main elements of a paragraph beside the main text. This can help readers decide whether they should read the main body of text.
Notes
Notes can provide additional information, commentary or cross-references and lighten up your text. Use them sparingly and only for nonessential information.
Formatting and fonts
Typographical embellishments, such as boldface print, uppercase letters, small caps, italics and underlining can draw attention to specific parts of the text, making it easier for the reader to navigate in the text. However, they can quickly distract, cluttering the page and defeating their intended purpose. Keep them to a minimum. Your pages should look clean and coherent, not flashy. Stick to one typeface and size, and only use typographical variation for good reason.
Glossaries and indexes
A glossary is a useful tool in a book containing a lot of technical vocabulary. It is an alphabetical list of important terms, with explanations and definitions. It is not a substitute for explaining them at first occurrence in the text. A glossary should also not be an excuse to complicate the jargon unnecessarily.
An index makes information accessible by pointing to all the specific places in a book where pertinent information appears. The most basic type of index is composed entirely of main entries, with no subentries, but most publications benefit from an index with subentries. Main headings are the words the reader is likely to look for when consulting the index. Subheadings are used to make the information easier to find, keeping the headings from being followed by long lists of page numbers.