I just saw these this morning off a FaceBook post and felt compelled to share this with the rest of you all in case you haven't seen it before and you struggle with vehicle highlights like i do:
http://modelbrush.com/free-pdf-guides/
The files are located under the airbrush heading and has two pdf files that show you the three major ways of highlighting the large flat surfaces on vehicles like tanks. Now if they could do one for robot constructs!