I would suggest 1st creating a
new folder in any one of your Shared locations. Then open a new Word doc within that folder, click on the Styles icon, select any template and click on the little down-arrow to the right of the template's name, click on Modify, and set up your customized template exactly as you want it. You can also change the name of the new template to anything that you want.
When you're done customizing your template, be sure to check (at the bottom of the screen) "New documents based on this template." So long as you create any other documents within this folder, they should automatically be saved to the new folder. And just be sure that for each one, you remember to utilize your customized template.
Here's some additional help:
How to manage templates in 2007 Office programs and in 2010 Office programs Templates -- Create Word Templates Quickly (Word 2007 but should work in Word 2010 also) Templates -- Create Word Templates Quickly Word Templates -- Saving Your Document as a Word Template