Hi
Create a conditional formatting rule
- On the View tab, in the Current View group, click View Settings.

- In the Advanced View Settings dialog box, click Conditional Formatting.

A set of default rules appears, including the Unread messages
rule. This rule makes unread messages appear bold in the message list.
In addition, any conditional formatting rules that you created in the Organize pane with a previous version of Outlook appear.
- Do any of the following:
- To delete a rule, click the rule, and then click Delete.
- To temporarily turn off a rule, clear the check box for that rule.
- To change the criteria for a rule, click the rule, and then click Condition.
- To change the text formatting that is applied to a rule, click the rule, and then click Font.
- To add a new conditional formatting rule, click Add, in the Name box, type a name, click Font to specify the formatting, and then click Condition to specify the criteria for this rule.
Example conditional formatting rules
These are some examples of conditional formatting rules that you can create in Outlook 2010.
Follow steps 1 and 2 in the previous section, and then do the following:
Make all messages from John Kane appear in red
- Click Add.
- Enter a name for the rule.
- Click Font.
- Under Color, click Red.
- Click OK.
- Click Condition.
- In the From box, type John Kane.
Note The name must exactly match the full name that appears on messages you receive.
- In the Filter, Conditional Formatting, and Advanced View Settings dialog boxes, click OK.
refer link
http://office.microsoft.com/en-us/outlook-help/automatically-change-incoming-message-colors-and-fonts-based-on-sender-subject-or-recipients-HA102054868.aspx