The fact that you are reading these pages indicates that you already believe that performance is an important coding issue to you. Consequently, I will be dispensing with the sales pitch for optimization. However, I would like to discuss my approach to performance optimization so as to provide some perspective on the specific optimization techniques presented here. However, I view performance optimization in a much more general way.
Optimization is a top to bottom and beginning to end process.
The sooner you make at an issue in the development of you application the more effective it will be. This does NOT mean that you should optimize every line of code you write. It does mean that you should identify potential performance problems as early in the development process as possible. Frequently, the best solution lies at a much higher level. For instance, do you really need to update the entire screen 4 times a second, do you need to calculate the standard deviation after each number is added to the list, etc.