How To Create Tiles With Custom Colors On Start Screen

Solution 1:

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.

Solution 2:

Currently, there is no built-in method for customizing start screen tiles in Windows 8. However, with the use of the third-party program: "OblyTile" (found here), you are able to define custom tiles that will open applications.

You are also able to set up shortcuts to folders if you target "C:\Windows\explorer.exe" and set the arguments to the URL of the folder.