Although email security has certainly improved since its inception (such as the implementation of encrypted passwords), it is far from being a completely secure means of transmitting important information. For example, an email does not simply go from the sender to the recipient instantaneously.
1. Make sure that your list is opt-in.
2. Have a clear and simple unsubscribe process.
3. Wake up inactive subscribers.
4. Be careful if you are promoting affiliate products.
5. Do not use shortened links.
6. Know the real reputation of your email service provider (ESP).
7. Watch your sender reputation
8. Check your sending IP against blacklists.
9. Follow best Gmail email practices.
10. Sign up for a Gmail postmaster account
Attention: "role based name" email prefixes such as support, webmaster, info, contact, forum, service, affiliate, admin, traffic, partners, marketing, etc., for our member accounts are not permitted. They are acceptable for a vendor listing, but not for the member email. This is due to bulk email processors scrubbing them for delivery due to extremely high bounce rates. Please apply for membership using a personalized email prefix. Something like firstname.lastname@example.org.
If we discover you signed up with a role based name we will give you only one message to change it. After 3 days your account will be removed if the email is not changed.