Email clients use a variety of technology to render HTML, so email formatting will vary based on the program used to open it. The most noticeable differences are observed in Microsoft Outlook. Since Outlook uses the MS Word rendering engine, it does not respect modern HTML and CSS standards. The following tips will help to resolve these common styling issues.
 
1. The following styles should be avoided for Outlook compatible email designs.
 
- Instead of float use: align
 
ex/ align="left" 
 
- Instead of margin use: vspace
 
ex/ vspace="10"
 
- Instead of padding use: hspace
 
ex/ hspace="10"
 
 
 These issues often arise with image formatting, because Outlook does not support margin or padding around images. Use something like this to achieve the same result:
 
<img src="http://www.blackbaud.com/example.jpg" align="left" vspace="10" hspace="10" />

Notice the "vspace" and "hspace" can be placed anywhere in the tag of the element you are currently adjusting. 
 

Avoid - CSS

Use - HTML

float
 

align=”left”
 

margin
 

vspace=”10”

padding
 

hspace=”10”