Great! Are you planning on discussing placement of features, or just the linework itself? Specifically, I'm thinking of the bit where you talk about making sure to incorporate river mouths, capes, etc into coastlines. It might be nice to see zoomed-in views of examples in your coastline and a sentence rationale for why they might be in one place as opposed to another. But, if that's expanding the scope of the tutorial more than you want, feel free to ignore me!

Also, why not include a little more detail on the mountains? It's not too much to embellish them with ridgelines and so forth, and it can be important in planning out how to lay out the lines to know how those features will appear. (I admit that having an idea in advance is less important in Photoshop than it typically is for me. )