To zoom into a particular area in a QuarkXPress document, hold down Control-Shift and drag a marquee around an area of your page. QuarkXPress will magnify that area to fill your window, or to 800%, whichever comes first.
Other timesavers: press Command-0 to fit the page to the window. (Windows: Ctrl-0) Press Command-1 for 100% view. (Windows: Ctrl-1)
For other views, press Control-V to highlight the View Percentage area at the bottom left corner of your document window, and then type in any view percentage you’d like. (Or type T to view your document as Thumbnails!)