Everyone is inundated with so much information each day that you must keep your emails short and to the point. Use humor whenever possible, but avoid going "over the top" or you will lose your audience. Write in an interesting, crisp and professional manner. Make sure that your email has a purpose and that you know what you would like in return from the recipients.
If someone asks to be removed from one of your email lists then do so quickly with no questions asked.
Your email marketing will work best if you have a written plan. This will force you to really think about your email goals and objectives, and the planning will show through to your customers and potential customers.
Have some fun and be creative about how to use email.
Talk to others who run their own businesses to see what has worked for them. Test the waters by writing a plan and then doing several emails to each of your email groups. Gauge reactions and make any changes that will help you be more effective. What are you waiting for....start writing those emails!