Use your Company Colors and Logo
When possible, use your company colors and logo. The recipient will recognize your communication, especially if your templates are consistent, and won't hit the spam/junk button. But, keep in mind a pretty email is nice to look at but the most important thing is getting your information to your subscriber so don't get too fancy with the design. Lots of design elements will get stripped out by mail clients and Outlook will display hardly any of them.