Here I added another layer and named it "dark". I pick black and adjust the alpha again. (I blurred it with the blur filter) I'll keep adding layers for the darks (darks2, darks3, etc.) and change the degree of alpha. I'll add even more layers for the clothes and use a darker version of the original colors and adjust the alpha on each to add shadows. At the end I'll add white layers for hilites, again using different alpha settings. Finally, I'll add a background and a drop shadow. Add as many layers as you need and work away. Now that you understand about the different layers needed, I'll just show the progress from here on in, changing things as I go if needed.
Exported, cropped and resized. I hope you got at least something from this tutorial. I know it was longer than the Bible but you should at least now have an idea about how to do a caracature. Thanks for following along and I'll see you on the forum.
One more personal tip before I go. Look at my final drawing. If I show that to someone and ask who it is, hopefully they'll say "It's Tom Hanks". Now look back on the drawing next to the photo. It doesn't quite resemble the photo. The lesson? When you create caricatures or portraits, paintings, etc. don't show the original photo with it. People will pick your drawing to shreads and point out every mistake compared to the original. Show them your ART, not your REFERENCES! We're not photo copiers, we're artists damnit! :-)