I don't know how many will agree with me, but I believe it's more about the skills than the medium itself.
Of course that having the knowledge of the medium will help, but a good artist will do good with practically any medium, because like Richard Schmid said (I guess he said this) : "I'm here to teach you how to see". Or something like that :-)
I do have a video called " basic pastel portraits with Jon Davis".
I guess that I got it from an Amazon vendor, but I'm not sure.
The price was good.
Here are two links :
As you can see, they appear both when selecting one of them.
They're PAL format, but I guess that's not an issue anymore.