One of the very first things you should do before writing a line of application code is architect the application tier to maximize and exploit the ASP.NET Cache feature.

You simply need to include a reference to System.Web.dll in your application project. When you need access to the Cache, use the HttpRuntime.Cache property (the same object is also accessible through Page.Cache and HttpContext.Cache).

There are several rules for caching data. First, if data can be used more than once, it is a good candidate for caching. Second, if data is general rather than specific to a given request or user, it is a great candidate for the cache.