My question is closely related to this question but for a much later version of Outlook.
I have been using Outlook 2010 at work on Windows 7.
The system I have setup for the past 6+ months is using categories to allow quicker sorting, filing, and management, similar to the gmail system I have used before. I have a variety of shortcuts and macros setup (using AutoHotKey and VBA, for those interested) for quickly doing all these activities. I started this setup realizing how often I had to search for email even in folders once folders got to a certain size, so I stopped trying to file them when I had to search anyways.
Unfortunately, the built-in search within Outlook is inferior to either the Mail app for OS:X or Gmail's search and even with only about 6 months of emails is really slow.
I am looking for a way to make this search faster and more accurate.
First ensure that Windows Search is turned on (Control Panel / Programs and Features / Turn Windows features on or off).
Second, ensure that the outlook folder is used in Outlook Options / Search / Sources / Indexing Options. Check that there are not too many other folders listed, to minimize the size of the index.
See also this article.
As another optimization, you can reduce the part of the index to search by using Advanced Find.
Another solution would be to use a search replacement for Outlook's search, for example Xobni, Copernic or Lookeen.
Another alternative used to be Lookout, which Microsoft bought and canned, but maybe these articles may help :
Lookout: a powerful search function for Outlook
How to Install Lookout on Outlook 2007
Search e-mail at lightspeed: using Lookout with Outlook 2007