the opacity masks? I don't use cell shading.... the only example i have up is the face of [link] i lay down flat colors, them shade/highlight with layers set to clipping masks that are in muliply/screen/normal/etc. and go to work with my tablet (or the school's cintiq's - i am so spoiled). i have a much better example of that, but it's unfinished so it's not up yet. it uses the same technic, but looks way better than that example. i guess i don't think this is the best aplication of clipping masks, but it's still a useful tut because people should know about clipping masks, because they're very handy.
In the Layers Pallet, you need to right click the layer and one of the options will be Create Clipping Mask. Other options would be selecting the layer and either go to the top of the screen and click Layer > Create Clipping Mask or pressing Alt+Ctrl+G. Hope that helps. ^_^
Interesting, I've never used Clipping Masks since I understand Vector Masks much better But another Photoshop tip never hurts.
A couple suggestions on the tutorial itself, though. When dealing with different layers it's useful to point out on which layer one should be working on. For example, the Wand selections have to be done on the finished layer, but the gradient has to be applied on the layer below it. Pointing out the need to switch layers between those steps will help eliminating possible confussion.
Second, I would recommend lowering the saturation of the red texts, they vibrate against the grey background and white text, thus making it a bit straining on the eyes.
Yup the entire thing was made in Photoshop. I fixed the issue with the coloring by making it a darker shade of red. That and I specified my layers more. I hope the tutorial helps you the way you help me, Shnek. ^_^
Sadly I don't know any tutorials, all my instruction on it happened in college. But I'm positive dA has a bunch to offer, just don't go down the "tracing animu pics" road, it leads to the dark side
The best advice I can think of is to always remember that Photoshop and Illustrator are two completely different animals. So don't try to recreate what you can do on Photoshop in Illustrator until you've gotten more acquainted with it.
Personally I rarely use it to make art from scratch. I use it more when I have to work with much text and to handle layouts easier, like here: [link] The photomanipulation and drawings were made in PS, but everything was put together in Illustrator, since it was easier to play around with all the elements in order to get the ideal placement.