To continue your learning, I have a number of lessons in video only form. To watch some case studies, and see all of these tools used together in action, as well as the introduction of more tools, you can watch the playlist below. Make sure to skip over the episodes you already saw over the course of this tutorial. There's over two hours of lessons here, not included anywhere else in this tutorial.
So at this point you’ve brought your two images into photoshop, cut the head out of one of them, and adjusted the colors and size so it fits the first shape. Not only that, but I gave you half a dozen ways to do each step and you know what? You now know the fundamentals of photoshop. You can now combine any amount of images together to your hearts content. I tried to error on the side of over explaining and will make sure to answer all questions asked and rewrite this tutorial as needed.
Many times using only the techniques taught above I’ll find myself with a photoshop document with 100’s of layers that turn out quite nice. In fact, I don’t remember the last photohops picture I worked on that had fewer then 100.
There’s a few places you can go from here. The best course is to use this knowledge and have fun making a few images, mastering the hot keys and navigating around. Get good and fast at tracing, color correcting, and coming up with inventive ways of combining these steps in unique orders. Once you’ve done that I have some more tutorials if you want photoshop for a specialized use. Because I'm well aware I have yet to get through it all, I've started posting external links in the form of ads on the right (so google can save me the bother of finding the relevant sites). Also, you can read my advanced tutorial on how I assembled a complex digital collage scene. (Essentially pushing everything you’ve learned here to the limit – far further then you knew it could go.) If you haven't watched the videos yet, go ahead, as I consider them extremely helpful.