If you hand-sort your email, you’re living in the past! You should use rules to automate your email management.
A rule is an action that Microsoft Outlook performs automatically upon incoming or outgoing messages, based on conditions that you have specified. You can create a rule from a template, from a message, or using your own conditions.
The Rules Wizard includes templates for the most commonly used rules, which include:
Stay Organized. These rules help you to file and follow up on messages. For example, you can create a rule for messages from a specific sender, such as Bobby Moore, with the word "sales" in the Subject line, to be flagged for follow-up, categorized as Sales, and moved to a folder called Bobby's Sales.
Stay Up to Date. These rules notify you in some way when you receive a particular message. For example, you can create a rule that automatically sends an alert to your mobile device when you receive a message from a family member.
Start from a blank rule. These are rules that you create without the aid of a rule template and that you can completely customize.
The simplest way to create a rule is to start with a message.
You can also create custom rules from scratch, and edit existing rules.
For more info, see Microsoft Support: Outlook: Managing Messages by Using Rules
Rules work basically the same in Outlook 2003 as Outlook 2010. You can right-click messages to create rules in the same way as Outlook 2010. To create a custom rule from scratch, or edit your existing rules, click the Tools menu, then Rules and Alerts.
For more info, see Microsoft Support: Outlook: Managing Messages by Using Rules