While you can pin any application to the new Windows 8 start screen, there is no option to pin a commonly used file. Say for example, if you use a particular file, a document or an excel sheet daily, then it is always better to pin it to start screen so that you can open it quickly. The new start screen is one of the major changes to Windows 8.
Tile A File is a simple freeware tool which makes tiles on your Windows 8 Start Screen for files that you commonly use so that you can quickly launch those files in the future. The application supports both square and wide tiles and displays the thumbnails for your files on the tiles that it creates.
Tile a File allows you to launch an application associated with a file (e.g. like Microsoft PowerPoint for viewing a presentation) with a single tap rather than having to go to the Windows desktop to find the file and run it.
If you manage multiple files on a daily basis, this app is pretty good.