Once you get your email message opened, your next challenge is to get the reader to click through. So make it clear how to click through to buy, try, or do whatever the purpose of your mailing is: 

So instead of a embedding a link in your text (“Click Here” – a term to avoid), you’ll get better results if you make the desired action visible, including making a tag line in a  larger size of font size than the rest of your text and place it above a bullet containing your hyperlink.

My latest book with just two clicks!