If you apply heading styles to section or chapter titles in your document, then turn on the Navigation Pane (View tab, Show group, Navigation Pane check box checked). You will be able to jump to different sections without beating up your Page Down and Page Up keys! To easily assign heading styles, use the Ctrl+Alt+1, Ctrl+Alt+2 and Ctrl+Alt+3 shortcuts to assign Heading 1, Heading 2 and Heading 3 styles respectively.
Have to refer back to certain sections of your document that aren’t necessarily notated by a heading style? Use a Bookmark! Click into the area you’d like to mark. On the Insert tab, in the Links group, choose the Bookmark button. Type in a name for your bookmark, like “needs org chart diagram,” then when you’re ready to start adding illustrations to your document, you use the Ctrl+G shortcut to “go to” your bookmarks.
Thinking about doing a Find/Replace all, but not sure if it will give the desired results? Using the Browse the results… tab in the Navigation Pane will show you the results, in context everywhere they appear, giving you an opportunity to predict the outcome of a global change. Have an older version of Office? Just use the Find dialog box (Ctrl+F) and choose the Reading Highlight button to highlight the search results all over your document.