You need to mostly master C++ first, creating some projects that manage pointers and memory, and should try creating some tools using the Windows API or some Linux box before you even touch graphics programming.
Next stop once you can handle the C++ code necessary, you should tackle some OpenGL or Direct3D tutorials (and download and setup the API(s) you choose to learn) which teach you how to create a display window, get a system up and render some primitives to screen.
Here are some links to get you started if you are a Windows programmer:
http://www.cprogramming.com/tutorial/opengl\_introduction.html (An OpenGL getting-started tutorial.)
http://www.directxtutorial.com/Tutorial9/tutorials.aspx (A Direct3D getting-started tutorial.)
http://www.spacesimulator.net/tutorials.html (Ideas about 3D objects/space programming for graphics and physics systems.)
Once you can follow the above examples, you should consider buying a book to teach you fundamental concepts about 3D graphics rendering, and you can just go on from there.