Another favorite tool in my pencil case is General’s Sketch & Wash Pencil. It’s water-soluble graphite. I enjoy it, as up to this point in time, I don’t have the patience to create shaded pencil studies. I do love working in black and white. You can concentrate on tones versus color and in the end, these studies will help you work with color.
I drool when I look at the drawings of Debby Cotter Kaspari. They make my artist soul want to push the comfort envelope and give the ‘pencil’ another try. We’ll see what this year brings 🙂
For now, though, I want to make sure you try your hand at the sketch & wash pencil. They come in a 2 pack which includes a metal pencil sharpener. This pencil will also add another shade of black to your watercolor pencils. Sometimes black is just too black and the tone of the graphite does the trick.
Both the storm studies above and the trees to the left were done on watercolor paper. 
The sketches of the egret were done in my AquaBee Super Delux sketch book. A fun exercise is to draw just the shaded areas of your subject. This was my quest while observing this Great Egret hunting.
You'll enjoy working with the s&w! I know there are other brands of water-soluble graphite out there but haven't explored them yet.
I enjoyed that quick time of egret sketching. I just wish the scan of the page was of better quality. Some of the graphite is so light that when I tried to get rid of the background noise, I'd lose some detail. Oh well.
What a nice page of egret sketches!
I’m unfamiliar with “General’s Sketch and Wash Pencils” but they look like they are one more tool to try in the future. They look like they might be particularly good for water and clouds as you have used them.
And as you say, it’s always a great pleasure to see The Motmot’s sketches.