The library folders where your documents, music, videos, contacts, etc are stored in are located in the users' folders by default. This is fine as long as you have everything on your computer on just one partition, but it may be helpful to relocate those libraries if you want to split your operating system from your data files on a separate partition because these folders tend to become the largest on the average home computer.
Before you start moving, you need to create new folders that will be used as libraries later on. Go to the location where you want to move your libraries to and create folders to replace the old ones (Desktop, Downloads, Favorites, Links, My Music etc.).
Now to get going, open your user folder, in my case that's C:\Users\christian. This is where the library targets are that you want to move. Start with any of them and right-click it, then click on Properties. On the Location tab, you'll see the path to the folder that the library is using right now, which points to our Users folder:
Click on Move... and a folder browser appears. Browse the corresponding folder that you have just created and click Select Folder. Now click Apply - if you had files in your old library target, it is recommended to move them to the new folder; Windows will do this automatically upon clicking Yes on the appearing prompt: