The Definitive "Hello World" Web Part Tutorial

Summary: Learn how to create and deploy a full-functioning Web Part for a Windows SharePoint Services site. In this article you will see how to accomplish each of the steps to take a Web Part from its earliest stages to being fully packaged for wide distribution. This article pulls together tips and instructions from many sources and ties them together in a seamless, step-by-step approach. (https://msdn.microsoft.com/office/default.aspx?pull=/library/en-us/dnofftalk/html/office07012004.asp)