Thanks to this nifty article on Exchange 2003 hacks by Exchange MVP Rodney Buike, I learned about the Contig tool. This tool, freely available from Microsoft as part of the SysInternals offerings, offers the ability to perform file-level defragmentation. This can be a good thing for volatile data files such as Outlook’s .ost file.
Don’t forget the basics, though. Keep the number of items in your Inbox down as much as you can, and try to keep the number of messages in any given folder lower than 1,000. Don’t be afraid to make use of folders and a hierarchy. Just as proper use of containers helps you keep physical stuff organized, proper use of folders will keep your mail organized.