If you prefer, it could be closed as being not constructive, as we don't know what Microsoft is using and there's no objective definition of what "professionally looking" is.

It's a safe bet to say that all professional e-mail templates are hand-crafted and thoroughly tested on various e-mail clients to ensure that they look good. And they're all not sent out via Outlook anyway. 

<sub>(No, it can't [import millions of contacts][1].)</sub>

If you wanted to ask how to stop Outlook from mangling with your previously created templates, that would—in my opinion—be a valid question to ask. But make sure you give a concrete example and provide screenshots, et cetera.


  [1]: https://superuser.com/questions/474177/importing-about-millions-of-contacts-into-outlook