There are 35 best practices that can be done for boosting your website, but, you don't have to worry of how you're gonna apply these practices, because Yahoo have created a tool called YSlow which is a Firefox add-on integrated with the Firebug web development tool, so you need to install Firebug first before YSlow. Below image shows the result page of YSlow.
It is a great tool to review your website performance. However, for those who use free web hosting, you're not allowed to modify the settings of the server. Hence, you might not get the best result when using YSlow.