Hi Raymond,
We have a lot of 'best practice' articles on this topic, but in general, after using the starter HTML tags, I'd recommend seeing these suggestions for designing emails for Outlook: http://blog.clickdimensions.com/2014/03/designing-emails-for-outlook.html
Outlook also does not render some CSS properties such as "float" and does not allow adding background images. There are also more resources on this type of perspective as well on the web.
Finally, you may also want to note that you can code responsive design in your templates and that lengthy emails can sometimes be cut off by Outlook.
Please let us know if you have any questions!