Character count: A good rule of thumb is to include, at the very least, 500 characters of text. A spam email often consists of 1 to 3 sentences with a single link within it.

Ensure your plain text matches the HTML version: Internet Service Providers (ISP), such as Gmail, scan the plain text version of emails for signs of spam. If your email does not include a plain text version or if the plain text version does not match the HTML body of your message, most ISPs will assume that you are trying to slip something past their filters.

Avoid text formatting: Spam filters do not like a lot of formatting such as bolding, italics, highlighting or changes in font (color, size, etc.). To get the best delivery possible, keep your use of formatting (especially on hyperlinks) to a minimum.

Use only one to two links: The point of an email is to get the patients to visit your page, so those should be the only links in your email. Avoid including social media links, links to your site, terms and conditions, and privacy policy links unless relevant to the content of your email.

Include whitelisting instructions: Encouraging subscribers to whitelist your address is one of the best things you can do to boost engagement. The best time to do this is in your welcome email after they subscribe to your list. Ask them to follow these steps:  (1) Right-click on the message in your inbox, (2) Select “Junk Email” from the menu, (3) Click “Add Sender to Safe Senders List”

No raw URL: When sending emails, make sure to never send out a raw URL or public URL shorteners like bit.ly in your email messages. A simple solution is to use a hyperlink with anchor text that clearly describes the destination of the link. This is also a much more attractive option than raw URLs.