Keep it useful
Be specific and concise, provide information related with your service that is really helpful to the user.
Link related content
Allow the users to choose what content they want to see next. You can get interesting metrics from their decisions.
Log in with one click
Include a button with an authenticated and automatically generated URL, to allow the user to log in with a single click.
Allow feedback to be sent
It is probably not possible to reply to the email sender account, so provide another way they can contact you.
Call them by their name
If you have their name stored in your database, you can include the variable on the email to further personalize it.
Completely customize it
Feel free to edit colors, fonts, the logo... and adapt the look and feel of this email to your brand’s style guide.