I also created a few shaders to help create a color theme as well as separate the parts according to color. This is a surprisingly useful technique since I was later able to bake out (painfully) a base color map from this. The different shaders also served to remind me which part was metal, which rubber, which had more shine or was duller etc. Here is the final high poly model (Fig.10).
I proceeded to build the low poly model. For this task, I just duplicated the high poly model and removed all creases. I ended up with a pretty good starting base, except for the body which I had to rebuild from scratch to get a closer fit. Then, using Maya's Transfer Map tool, I slowly baked out the Normal map and Color map. The color map was derived from the numerous shaders I had applied in the modeling process. This process took the longest of all as I kept running into problems I had neglected back in modeling. It pays to go through a model to check that all the normals are facing the correct side and not inverted. This is the baked result with diffuse and normal map rendered in Marmoset (Fig.11).
Then from here it was texturing time. Using the baked color map as base, I started layering all the dirt, scratches and battle damage. One thing I find rather useful is to overlay a layer of "rainbow" colors on top of your diffuse because it helps to create subtle hue changes. I set it to a very low value, about 1-2 percent at most (Fig.12). Once the diffuse was done, I then created a complementing specular map from the diffuse. This part of the process will be very brief if the layers in the diffuse are done with a bit of planning (Fig.13). A few Hue/Saturation layers, and inverting of those scratch layers will usually yield a pretty good starting Specular map.
Looking back at the high poly model, the critique I got was that the legs were very bare of details, and the sculpt lacked secondary details. I proceed to draw panel lines (Fig.14) and using a wonderful Photoshop plugin called NDO, I converted those to normal maps and overlay them onto my original normal map. Some might compare it to Crazybump and most would prefer Crazybump, but I find being able to draw and create normal maps without leaving Photoshop a great time saver!