Some of the things to be aware of with email marketing:
1) Have email campaign sign up prominent
2) Usually give something to get started with plan
3) Use to educate potential clients
4) Develop some reason to keep in touch with the user
5) Measure how well you are doing
6) Make emails user/client centric
7) Have a Call to action in your emails
8) Do not spam
9) Send it as HTML as well as plain text emails