How to create reusable document parts

Learn how to create templates from the people who make Word! 

There are some excellent tutorials over here thatI’d recommend:

“If you want to use a building block in documents based on one template only, you need to save a copy of the template first so I usually start there. You can also add a building block to the Quick Parts for all of your documents. I included the steps for both, below: How to create reusable document parts

http://blogs.msdn.com/templates/