Optimising your server side scripts such as ASP and PHP is very important for better utilisation of server resources. Even a high end server can fail to deliver the speed and performance that you look for, if the codes are not optimised.
Procedure
For PHP & My SQL:
[1] It is a good method to store connection string in a common file. This common file can be included as a header in all the pages, wherever it is required.
[2] IMPORTANT : Avoid using multiple loops in a single pages. Most of the programmers make mistakes in handling loops thus the asp pages will not be executed after few hits.
[3] Do not unnecessarily use asp pages. It is strongly adviced to keep the home page as ".html" and not as ".php"
[4] Table Size should be kept at minimum. Avoid opening multiple tables at a time. Moreover, avoid querying a single large table.