1. -An opt-in list. Wherever you have your list stored, make sure you have access to the original source of permission. Also include an opt-out link with a mailing address.
2. -The “from” name you want to use. Also include the “reply to” e-mail address that someone will check (or, if you are a company that cannot check these messages for security reasons, a strong disclaimer that replies will not be read).
3. -A really good subject line—not something catchy, but rather something that creates trust and interest in opening the e-mail.
4. -Links that work inside the content even if images are blocked.
5. -A strong reporting system on the back end to track bounces, opens and clicks.
Source: Jeanniey Mullen, founder, Email Experience Council