Principles are ways of successfully dealing with reality to get what you want out of life.
Ray Dalio, one of the world’s most successful investors and entrepreneurs, cites principles as his key to success.
Either literally or vicariously (through reading reports, job descriptions, etc.), temporarily insert yourself into the workflow of the area you're looking at to gain a better understanding of what it is that you are dealing with. As you design, you'll be able to apply what you've learned, and revise the machine appropriately as a result.