I started out with the idea of retaining the vertical "monoeye" and general color scheme from my old (current) textures. I had a few pieces of concept art that I'd seen a while back that I liked a lot but ended up looking up a lot more that I used as general inspiration or pulled interesting bits from. With all that open in a ton of tabs, I started sketching out some ideas for heads. I generally like to do my concept sketches as what I imagine the character looking like in "real life" as opposed to the spheres and boxes of Toribash, since that helps me with shading and shadowing and whatnot later on.
Initial concept sketching of head, shoulder designs.
Additional shoulder concept sketches.

Initially I just had the block of head sketches in the top half of the above image, so I started working up the V1 head. I generally start with just solid bland shapes with minimal shading added just for the sake of distinguishing pieces, but this screenshot's a little further along when I've started to add more shading to define angles and layering and whatnot, plus some little details that I threw on.


Tweaks to shadows, made the "eye" wider, some fiddling with highlights/shadows to better define shapes, found a nice scratched-up metal texture to add a worn-down look, added some more little details and whatnot.


Some (hopefully) fairly subtle gradients added to add some contrast across pieces per TomW's suggestion. Updated patterns with new brushed-steel pattern (courtesy wojtar-stock and carbon fiber (courtesy design-maker). After setting up the left shoulder I decided to make the arms asymmetrical, with the left arm more heavily armored than the right. This ended up creating a lot more work down the road since it involved looking up even more reference images for lighter armor than the left, then figuring out if/how they could be adjusted to be stylistically congruous with the left arm design, etcetera.


At this point I also sketched out some designs for the right shoulder based on all the nonsense I described above.

Gave the V1 head some Helghast-esque eyes for fun since I started looking at alternative designs. Might mess with this a bit more and sell it later.


Finished most of the left arm up. Wrists and hands will be saved for last along with ankles and feet because those are my least favorite parts.


I worked up the V4 head since there was a bit of a disconnect between the monoeye and the rest of the head in V1.


In addition to the pen & paper sketching, my current process involves a fair bit of drawing all over screenshots with my tablet. Here's that for the right shoulder and bicep (I selected the V2 right shoulder texture). You can hopefully tell that this makes it a lot easier to figure out the mapping on the template, as well as helping me to make textures flow more continuously into each other.

The miracles of layers also means I can turn off the screenshot and just look at what I've sketched out.

Here's the same thing for the right elbow and tricep.

Finished up the right arm, started work on the torso. This part of the process is definitely going to be one of the longest since there's so many joint textures overlapping in so many different ways.