When creating content for a new site, the first item to consider is whether it will be shown as a Post or a Page.
A Rule of Thumb
A useful rule of thumb is to make menu items like About, for example, which usually comprises static information, to be created as a page. The other items should be posts, grouped into categories. For example:
Too Many Menu Items?
To avoid too many categories, use Tags within categories. For example, Microsoft Office is a category; Outlook, Word, Excel, PowerPoint are tags.
If you display a tag cloud as a widget in a side column or footer, users can select all posts relating to that tag. For example:
The tag is shown at the end of each post as well. This post has the WordPress tag just below the content.