Set Reminders to Act on Messages. If you spend a lot of time in Outlook, this tip can really boost your efficiency. Easy as it is, it’s very underused. To set a reminder—visible in your Inbox–to act on or reply to any message, right-click on the message you want to set the reminder for, select Follow Up, and choose your Due By time and date. When you click OK, the message will be flagged [...]