Here's a video on how to shade on Proko that you might like. https://www.youtube.com/watch?v=-dqGkHWC5IU&t=592s One thing the video mentions is focusing first on shading primary forms, then secondary forms, then tertiary forms. For instance, with the legs you'll want to think about them first as cylinders and then think about the shading of the armor after that.

Hey! I think you would benefit from keeping yoour lighting situation simpler! In this drawing everything seems to be lit very much the same and the coat section next to his legs on the inside sould probably be way darker(just as an example). So just having one lightsource could make it easier. Also take a look at the way materials reflect light. I think his right cyborg rifle arm doesnt really look like it is made of metal. Anatomy is also very imortand for charcters as the pose needs to seem natural. For example the left arm sits kind of awkwardly. Overall i think you should keep yur concepts a little easier! There is no need to go that comlicated when you are just trying to learn! What allways helps hugely is looking at the process professionals go thru so maybe look at https://www.instagram.com/evenmehlamundsen/ The very first step he does is blocking in the big shadow shapes which is a good exale of why sticking to the Big, Medium, Small process is very usefull.