Windows 8 – How to Pin Custom Files to Start Screen

Tiles for Modern UI apps will use the background color of the application.

From here: http://social.msdn.microsoft.com/Forums/en-US/winappsuidesign/thread/edf26bd7-0fd0-4cef-bd0f-dcc7399c0f3f

Your tiles will use the background color of your application. This is specified in your Manifest in the first Tab.

Tiles for Desktop apps aren't set per tile.

From here: Set color for desktop application's start screen shortcut, this answer.

For desktop apps, the background color used on Start screen tiles and toast notifications is not configurable by the app itself. The color is determined by the Start screen color theme chosen by the user (PC Settings -> Personalize -> Start screen).

If you just want to easily group applications together see this answer, on this question:
Named Group of tiles (Applications) in Windows 8?

For creating custom shortcuts to files/folders as tiles see my question here:
Adding custom shortcuts to Modern UI

Any shortcut you create (including switches) you can simply right click and "Pin to start" which will create a copy of it in the appropriate places.

So for example, to add a folder to the start screen, see the answer here, https://superuser.com/a/491169/85165.
Go to the desktop, create a shortcut to the folder you want, then right-click the shortcut, Pin To Start.

1. Open Command Prompt (Admin) by pressing Win + X, A

2. Copy these lines:

   del %LocalAppData%\Microsoft\Windows\appsFolder.itemdata-ms
   del %LocalAppData%\Microsoft\Windows\appsFolder.itemdata-ms.bak
   tskill explorer
   

3. Right-click in Command Prompt and select Paste:

   

4. Press Enter.

5. You're done. Now the Windows 8 start screen will reset to its original state: