I'm going to attempt to answer this on a broader scale, so it should still fit if the question is edited.
Currently, one of our top tags is technique. However, when I look at those questions I don't see the tag actually adding any value to the question. Most questions we already have about actually doing the art could qualify for technique, but many of them don't have it.
If we applied it every question that was asking about the way to do things, technique we'd certainly be our top tag, without telling us much about the rest of the question. It's too broad, can be combined with almost any other tag, and needs to be combined with another tag to make any sense.
technique should be removed and similar tags avoided. We've taken similar steps for other tags, such as tools, which were overly broad and not helpful in the end.
In this case, that would leave us with pencil + drawing + shading vs pencil-shading (possibly + drawing). Since the single tag pencil-shading conveys all the necessary information in one go, and is a distinct skill set from drawing alone, I think it should be used instead of a combination of other tags.
Similar concepts will come up, such as coloring and tools and maintenance, where a "parent" tag about the medium/implement should suffice, unless the more specific tag represents a distinct set of skills and expertise and stands well on its own.