Where can I learn more about tweaking application performance?
At the time this book was published, there were very few resources for improving the performance of Microsoft .NET applications. However, one way to improve application performance is to make small changes to your code and then test, noting the performance gain or loss. Don't be afraid to get your hands dirty and have fun. Also, though not yet published at the time this book was published, Performance Tuning Microsoft .NET Applications from Microsoft Press seems very promising , written by a team of professionals at Microsoft who improve application performance for a living.