By default, the titles of the unread messages in Outlook are bold and in blue. If you think that is not strong enough, you can change them with the steps below:
Step 1: Go to the folder you want to change, normally the "Inbox" folder;
Step 2: In the View" tab, click "View Settings";
Step 3: Click "Conditional Formatting" in the new window;
Step 4: Check "Unread messages" box and click "Font";
Step 5: In the "Font" dialog box, select the format you like to have for unread messages. For example, we use "Bold" for font style, "Bigger" for size and "Maroon" for color;
Step 6: Click "OK" to close.