Here's How:

• Go to Tools / Message Rules / Mail, then click "New".
• Select the condition "Where the From line contains people", but you could use any of the options. For the action, select "Highlight with color".
• Under "Rule Description", click on "contains people". You can type in addresses or domains (spearstravel.com) then click "Add", or click on the Address Book and select names from there. When finished click OK.
• Next we want to choose a color. Click on "color" and a little box will appear. Click the arrow and a palette will appear, from there just choose a color. Then give the message rule a name, any name will do!
• Now go to Tools/Options then click "Display" in the side column. Look down where it says "Labels".There are five colors listed with default labels: Important, Work, Personal, etc. You can change these by typing in the box.
• After you finish, click OK. Now, let's put these labels to work by using Message Filters...Go to Tools / Message Filters and select the email address you want to apply the filter to and click "New". Give the filter a name.
• Select the button marked "Match any of the following". Where it says "Subject", click the arrow to reveal the drop down menu options and choose "Sender". If you want the filter applied to a whole domain (like "spearstravel.com"), then leave the next button as contains. If you are filtering addresses, you can change it to "is". Enter the email address or domain in the box. To add additional names, just click "More".
• Change the action to "Label the Message" by checking the box, then select the label from the next box. Click OK when done. Follow this procedure some more to create other contact label lists.
• Now, when you check your Inbox, messages from various senders will be in different colors, making it easier to notice them.