There is a simple trick using Resharper where you can easily create a new Guid directly in Visual Studio. Using Google i had a hard time finding this trick - but I have known it for years. So I thought that I might as well share it. This requires Resharper and a valid license for this.
You can use the command "nguid" in order to create a new Guid. It is invoked by typing "nguid" or just by start typing it (below I am only typing "ng"). This will give the below dialog:
If you hit tab or enter you will see GUIDs displayed:
You can then choose the guid and format that you like. This is very easy to use. There is no reason to go to online GUID generators or the like, as this come built into Resharper.
Let me know in the comments if you had any problems with this :)