Thanks, ekipage, I hope you will find it helpful!
TheLost, pretty much. I tend to sketch on the shadows over the basecoat and then glaze/layer back up to the midtone before continuing on to the highlights. On the previous images, if you look at the legs, you can see the shadows roughed in on top of the midtone. In this case, maybe midtone isn't the right word since I was using the Meadow Green and Surf Aqua mix... perhaps I should just say basecoat.
SaintToad, well I may have taken some inspiration from Big Child's Sharki figure. Though the box art for him might have even more blue in it than mine! As for the larger scale figures, don't worry about imperfections and just enjoy the models. I think working on larger scales is a great way to learn and improve your painting. I want you to keep in mind that I rarely get a figure right on the first try. I like to think of my first go at highlighting and shading as a 'rough draft.' Especially on key parts of the figure like the face and any other focal points, I'll take a critical look at it when I've finished the initial attempt. Maybe this shadow isn't dark enough, that highlight might be in the wrong place, or some blends aren't quite smooth enough. I'll remix the gradient of colors (dark to light) on my palette and go in to touch up whatever needs it. I'm not repainting the whole face, of course. I'm just focusing on the areas that don't seem quite right.
On this orc, my first attempt at the face was decent, but I took a second pass at it to refine some of the lighting and fix a few blends. Since then I've painted the arms and back (just finished a session on the right arm). But, since I was working on sections at different times, the brightness of the highlights doesn't quite match over the skin. Although it may not stand out in the photo, in person the left arm is lighter than the rest of the skin. So I plan to go back over the piece, knock down the light on the arm a bit and maybe up some of the highlights on the rest of the figure. While I'm at it, I may adjust some shadows too. My point is, on these larger scale figures, I think it's easier to go back in and make adjustments when you need them. Don't worry about getting everything perfect. You can also continue to edit and correct things later until you're happy with the end result.