Summarize the following:
The area you or your organization writes in likely already has a preferred style guide. If you want to create your own, consider starting with the preferred guide. It can give you an idea of what you want to include in your own. You don't have to write a whole new guide if another one covers the bulk of what you want. Instead, you can just note how your company differs from the main style guide. Decide what sections you think your style guide needs. Write clear headings for each of these sections, and establish a well-thought-out order for the sections.  For instance, you may want sections on common mistakes, your organization's stylistic choices, tone, formatting, and preferred words and acronyms. At the end, you may want a quick reference section and an index. Divide these sections up with subheadings as needed to make it easy to flip through the guide. Add tabs to the pages after printing or use black markers printed on the edge of the page to delineate sections. The table of contents establishes the structure of your guide, making it easy to find everything else. Therefore, it should be right up front so your readers can find it easily.  To organize your table of contents, place the main headings on the page in a bold font over to the left. Place page numbers indicating where these headings are justified to the right. Add subheadings and page numbers under each heading in a regular font. If your style guide is on a website, place the table of contents at the top. Each heading should be a link to the appropriate section.

Summary:
Check out other style guidelines in your professional area. Create clear sections and headings. Make the table of contents one of the first pages.