Sure. Let me clarify first: The craft I refer to is the ability to create clear, detailed diagrams that not only document a system (like a layer 3 diagram), but also to express a series of ideas or concepts that a group of people is trying to wrap their head around. Effective use color, metaphor, and just enough text. These people obviously are not just artists...they need to understand what they draw. This is rare skill. Pictures can sell ideas, gain consensus, and move things ahead faster than a dozen emails and conf calls. Especially with Management. You won't get the attention of management with a 20 page dissertation...much less change their mind. I know, I have tried. In one case, we were trying to convince an army of execs to invest (substantially) in a large re-write. We had explained in detail, why it was needed. In the end it was a single diagram that sold our idea. We showed them how ugly the code base was with a cyclic dependency diagram. That hit them square in the eyes. We got the funding after that.

These people are hard to find...but you can (as I have) try to emulate them. I can suggest some books...I started with Edward Tufte's. Beautiful diagrams...and why they are beautiful. You can also look into the various "Napkin Books" from Dan Roam.

When I find a particularly amazing diagram, I keep a copy of it for reference. It helps me structure ideas and how I will communicate them to my leadership or my team. You can, with care, put an awful lot of data on a single page.

Again, make a lot of diagrams. If a concept, workflow, procedure, etc moves from unknown to known (mechanism by which this happens is not important) , draw the picture and send it out. If it never gets used again, at least you practiced the drawing and people know you can do it. Develop a style. A color palette. Certain styles of arrows. The list goes on.

Tooling: I love Visio. Damn, it's a fun tool. There are a few web-based tools... Omnigraffle, Lucidchart... not as good. At least for me. You can bang stuff out fast in Powerpoint, too. I keep a big pile of templates that I have massed over the years. Never used photoshop...not even once. Although, I keep inkscape and gimp around if I have to muck with actual images...but I really try to avoid that.