This is the introduction to a video series on how to write like an architect. This is another way to modify your writing. While its not longhand, it may be a good solution for someone looking for something geometric and would be great for addressing envelopes.
I used to watch the architecture students practicing this technique when I was in school. As your skills improve, you will not need the straight edge for notes or daily writing but may still want to use the straight edge for more formal situations.