Each of us have our very own methods which we cling to. A commission arrives and I begin by working out the main shapes in pencil, then I draw in the details in micron pen.
(Often- I work from a photo. I do enjoy working from real-life.)
Once I feel that I am ready to layer in the water-color, I begin by narrowing down my palette and go from light to dark. The paper of choice is Aquarelle Arches Block, either cold or hot press. There is something comforting about working on a block, as the paper stays put - Most works are done on a 9 x 12 block, but I love working on the larger blocks too.
I squint often to get to the right value for color. Capturing the light and the shadows are so important to me. Time has a way of getting away from me, but I work with an hour-glass nearby so that I have some gauge of time. Do you have a method or a process that works for you?