The most common way for emails you send to wind up in junk mail folders is from users reporting the message as spam in free email providers like AOL, Yahoo, or Gmail. When a message is reported as spam it causes other messages you send to potentially get directed to junk mail folders as well.

Make sure that you are sending emails only to current members who have opted into receiving the messages. Remove any non-current members from email lists.

Have recipients that find a message in their junk folder click the NOT spam button to help the reporting. That will also help future emails from your sending email address go to the users main inbox.

Most email providers offer a trusted sender list either based on the recipients contact list or based on a separate list of approved senders. Have all members and important contacts add your sending email address to their trusted/allowed list in their accounts.

Tell all members and important contacts to add your sending email address to their contact list. This will ensure that emails go to the inbox.

Consider sending messages from an email address other than info@ your domain. Some email providers will spam score messages from generic account names higher than emails from unique account names. In the admin area > settings tab > edit website settings link add a sending email address to the Set Broadcast From Email field. This will be the sending account for all broadcast messages from the website.