Email newsletters are very simple affairs. Simply write a letter to your customers providing them with helpful tips. Include information on your products and services. Remember that letters are still regarded as personal forms of communication. Make your newsletter's tone conversational, friendly, and informal.
Electronic mail is the marketing tool of the very near future.
We haven't gotten all the bugs sorted out of it and many people do get irritated at receiving mail they aren't interested in. BUT, email is cheap, conserves natural resources, and doesn't pollute the environment. That's a combination of strengths that will ultimately overcome all challenges in a very, very big way. Finally, write articles for one or more of the thousands of new on-line publications. The Net is about information.