First start going to town whatever electronic devices you decided to assimilate into the collective. Use anything you want: Stuff lying around, spare components, there are no rules here! Most of our bits came from a busted hp inkjet printer and two dead hard drives; along with a few other assorted components.
Grab that glue gun now and start gluing stuff to the chest piece of the shoulder pads and mask. Just stick on whatever you think will look good. Add a few wires. I also glued a few pieces to the shoulders themselves. You can add stuff to your assorted arm and leg pads too.
Above: the unpainted painted mask. The pixel ring is only attached for fitting and was removed for painting. I used some foam packaging behind the ring to get it to sit flush.
Once you've got all your bits glued you can give everything generous coat of black paint. May need more than one depending on how well it sticks to the materials you've used. Give those other pads you may be using a paint job too.
Now you can leave everything just a flat black but you can great weathered look with a couple layers of dry brushing. First I drybrushed the components with a mix of bronze and dark brown acrylics to create a rust colour. Then another layer of metallic steel acrylic. Experiment with some spare pieces to get the look you want.
If your not familiar with dry brushing techniques you can check out some basics here. You can see the effect below.
The armour pieces are pretty much built. Now onward to the electronics.