There is one particular built-in, time-saving feature I use constantly that I find many often overlook. Called the "Quick Look," this method of displaying documents was actually introduced in Mac OS X Leopard (Version 10.5) back in 2007. Although it does not work for every type of document out there, Quick Look lets you view the contents of a large variety of files instantly and without having to open a memory-sapping application such as Adobe Photoshop. If you have a particularly slow machine, Quick Look will hold even more value. With the icon of the file you want to view selected, all it takes is a press of the spacebar to read a PDF, view a PowerPoint, scan over a spreadsheet, or listen to an MP3 file without launching any program. Clicking on any other icons with the Quick Look window open will display that file as well, letting you rapidly view documents. Pressing the spacebar again closes the window. It really is a quick and efficient way to scan through the contents of multiple files without having icons bouncing in your Dock or the entire Adobe Creative Suite slowing down your machine. There are also a number of free downloadable plug-ins that can expand the capabilities of the Quick Look feature such as including more file types, adding support for animated GIFs, and viewing the contents of a ZIP file while it remains compressed.
For Windows 7 users, in Windows Explorer it is possible to use the Alt+P keyboard combination to preview the contents of some files in an embedded panel within the interface. However, this preview option does not support quite as many filetypes as Quick Look and does not have the window resizing and paging capabilities. Fortunately, there are a number of freeware Windows applications you can install to approximate some aspects of the Quick Look feature such as Foxit PDF Reader and Picasa Photo Viewer.
In my duties as an instructional designer, I find that I use Quick Look on a daily basis. I usually have the Mac and Windows operating systems running simultaneously via Parallels software. In addition, I may have a number of programs open at once such as Groupwise, Safari or Firefox (with multiple tabs), Articulate Storyline, Dreamweaver, Photoshop, Flash, and Acrobat. Quick Look lets me zip through a list of Microsoft Word documents or view a series of Quicktime videos while leaving all of the previously mentioned applications open and not launching any new programs. I have found it to be a real time-saver and would highly recommend that Mac-based instructional designers take a second look at Quick Look.