I was recently talking with some good friends about tips for performance and what an IIS Administrator could do on the server side. I also see this question from time to time in the forums @ http://forums.iis.net. Of course, you should test individual settings in a controlled environment while performing load testing before just implementing on your production farm.
Run FRT for long running pages (Failed Request Tracing)
Sql Connection pooling in code
Look at using PAL with performance counters ( http://blogs.iis.net/ganekar/archive/2009/08/12/pal-performance-analyzer-with-iis.aspx )
Look at load testing using visual studio load testing tools
Look at CPU, Memory and disk counters. Make sure the server has enough resources.
Same machineKey account across all same nodes
Localize content vs. using UNC based content on a single server (My UNC tag with great posts)
ETAG’s the same across all web-farms
Use YSlow or Developer tools in Chrome to help measure the client experience improvements.
Additionally, some basic counters in for measuring applications is: I would recommend checking out the Chapter 17 in IIS 7 Resource kit. it was one of the chapters I authored. 🙂
Request Per / Sec,
I strongly suggest testing one change at a time to see how it helps improve your performance. Hopefully this post provides a few options to review in your environment.