Using Sender Colors to manage emails:

Here's a simple tip that everyone should know about. You can change the background and text colors of the messages in your Inbox to add visibility to messages that need immediate attention. We all get a lot of email, and it's easy to miss things here and there. Lots of times, we know where some of our more time-sensitive messages come from.

To do this, go to the Mail section of your Notes preferences and navigate to the Send Colors tab. You can also add more than one name to each color.