You can use the following general guidelines when you improve your application and the environment in which it runs:

• Set performance targets early in the software design stage. If possible, try to estimate an acceptable performance target early in the application development cycle. Certain usage scenarios dictate the performance requirements. It would be disappointing to fully implement a product feature and then find out that it is too slow to be useful.
• Understand performance characteristics of the application framework, and employ the strategies that maximize the efficiency of components and operations.
• Understand performance characteristics of the application code. In medium-sized or large-sized projects, it is common for a product feature to use codes or components written by other developers or by third-party vendors. Knowing what is slow and what is fast in dependent components and code is essential in getting the design right.
• Do not attempt to test a large application's performance all at once. Rather, test small pieces of the application so that you can focus on the relevant results instead of being overwhelmed by data.
• Test the performance of your application early and often. It is always best to identify problem areas early and resolve them in an iterative manner, rather then trying to shove performance enhancements into existing, poorly performing code at the end of your application development cycle.
• Avoid optimizing code too early. Even though early testing can highlight performance hot spots, refrain from fixing them while you are still developing those areas of the application; doing so might unexpectedly delay the implementation schedule. Instead, document the issues and prioritize all the performance issues as soon as your team finishes the feature implementation.