HTML Design Email Guidelines When Sending HTML Email:

• Send yourself a test message to get a preview of how the HTML email will arrive.
• It is very important that you keep your HTML email simple due to Email readers not interpreting all HTML email equally. It would be necessary that you test the HTML message with Outlook, Eudora, AOL, Yahoo Mail, Google's Gmail, Hotmail, etc.
• All images used need to be hard linked. In other words: <img src="btnSource.gif"> won't work but <img src="http://www.yourdomain.com/btnSource.gif"> will work.
• You can use CSS for basic fonts and colors but use it sparingly. Many email readers won't support or interpret it correctly.
• Use Inline CSS that is not linked to files. (Available inside the HTML email message)
• When using CSS, use it below the body tag as browser based email applications (like Gmail, Hotmail, Yahoo, etc) strip out HTML, HEAD and BODY tags so that they don't interfere with their own web pages. (The web page displaying the email)
• JavaScript, ActiveX Controls, Flash and embedded movie files will normally not work. The reason they will normally not work or not work properly is because most people have antivirus software that will block these.
• Background colors and images will normally not work with browser based email services like Gmail, Yahoo, Hotmail, etc. The reason for this is that they strip out HTML, HEAD and BODY tags from HTML email received.

Spam Filter Details and Guidelines When Sending HTML Email:

• You will need a good balance between images and text else spam filters will flag the email as spam.
• Make sure your HTML code has no errors and ensure that your email message contains proper grammar and spelling. Spammers are renowned for sloppy HTML code and grammar.