Make the sign up process confidential and easy
When you ask customers to sign up, you should only ask for details that are vital for your business such as first name and the email address. It is advisable to make other details that may not be so vital for your business optional.
Assure the subscribers that all the information they provide will be kept private and they can opt out if they wish to.
Note that people who offer you the opportunity to send them e-mail have high chances of turning to be your business customers.
Let your lists be segmented
It is not advisable to send a single generic email to everyone. Your lists should be segmented into target groups. You can segment the lists using factors such as past purchases, location, surveys or job titles.
Then, you should develop e-mail marketing products that are relevant to the listed groups.