Many of the complaints are caused by the fact that the subscriber doesn’t recognize the sender and automatically assume that the email is spam. So be sure to  identify yourself in your email messages. And add clear that identifies you and your company in the beginning of your message, and reminds your subscribers of who you are and what they signed up for.

Contests very often prove to be a good way to generate traffic and buzz for your business. Create a contest and put a form on your site or in a pop-up box.  The entry “fee” is their email address.