Don't use the default New document button

The default New button in Word produces a blank document, based on the Normal template. As you know by now, you should be starting documents with custom templates, not with the blank document template.

So always choose File → New, instead of clicking the New button.

Better yet, replace the default New button with the New... button (equivalent to File ? New), so that you can use the button, but the button now produces the New Document task pane, allowing you to select a template for the new document.