ISA-101 is the standard for HMI design.
This is a good overview on some of the stuff:
http://wilmingtonisa.org/files/Download/ISA%2DApplying%2DISA101%2Dto%2DExisting%2DHMIs_MikeHawrylo.pdf
There is an international standard for the color of push buttons and such. IEC 60204-1. It's also an European machine safety standard.
You'll get the gist of the colors here:
http://www.schneider-electric.co.uk/en/faqs/FA28043/
You might have to take industry dependent or company specific color codes into consideration as well.
A few "rules":
* make it easy to understand and easy to use
* don't make the HMI screen look exactly like the machine or process (simplify it so it's easier to understand)
* don't use 3D objects (visual clutter, makes it harder to see what is important)
* don't use animation (it distracts)
* use color only when it means something (it's easier to see color that stand out that way)
* never use the color red for stop or stop buttons (harder to see alarm and abnormal conditions)
* use light/medium grey backgrounds (easier on the eyes and it allows you to use both white and black as different colors).
* think about what's important for the operator to see (not all the things you could show him)
* make it easy to understand what is an abnormal situation (for instance is this 231.2mm good or bad?)