Paul Randal provides a framework:
There are a huge number of best practices around SQL Server performance tuning – I could easily write a whole book on the topic, especially when you consider the number of different database settings, server settings, coding practices, wait types, and so on that can affect performance. For this post I decided to step back a bit from a list of specifics and list some general recommendations for how to approach performance tuning so that you maximize effort and minimize distractions.
Click through for several recommendations to make your performance tuning operations a bit smoother. None of these relate to specific performance problems. Rather, the post serves as some recommendations around how to approach performance tuning in general.