A Simple Win32 Window in CBy Dag, on December 30th, 2016
Here is a small example for making the most basic Win32 window. It is heavily commented to give a thorough overview of the different elements. You can download the example with its source code here.
This code is getting outdated, but still provides nice information about the different aspects that are still used. For a proper Win32 window, Visual Studio 2008 or later can provide an updated code skeleton that you can build on.