Many developers, being our nature and all, will attempt to wing this part of the exam. Do not make that mistake. Nothing is more important when developing server controls than a deep, thorough, intimate knowledge of the page lifecycle. You should know this aspect better than you know your spouse. If you do not have this deep understanding, you will not know that you should call EnsureChildControls() in Page_Init or CreateChildControls() in OnPreRender. Or when to manipulate session state, or load session state, or even when to inherit from existing server controls or to create your own. The best way to figure this type of thing out is to examine the existing Microsoft-supplied server controls via Reflector. You will see many patterns emerge as you do this and you will most likely learn more doing this simple task than reading a dozen books (as if there were that many) on the subject.