A good way to identify principles of design is to study each of them in isolation with a definition, an explanation, and examples of the principle.
Graphic Design studies include areas in different specialties: Human Visual Perception, Applied Behavioural Psychology, and Anthropology. A cross-subject web search will help you find/sort-out individual concepts. Many of the references of interest to us fall into "Marketing."
One reference I stumbled across was/is (in revisions) a kind of dictionary, cross-referenced by design principles, many (not all) of them of interest to us. It is not complete; but, it is an excellent start. I was so impressed that I bought a dozen/case and gave them to colleagues. Universal Principles of Design - A cross-disciplinary reference; William Lidwell, Kritina Holden, Jill Butler; 2003, Rockport pub.
A second recommendation is a comprehensive, organized, and well-written Principles of Form and Design; Wucius Wong; 1993, John Wiley & sons pub. This and Principles of Color Design, also by him, influenced Graphic Design courses taught at Concordia University, LaSalle and Dawson Colleges - Montreal, Canada among others. It presents the visual language of graphic design.
David B. Berman wrote do good -design-, How Designers Can Change The World; 2009, New Riders; which gives us our ethical principles to guide our designs to be truthful, ethical, and sustainable design. It is sponsored by the AIGA and others. The message is, "Don't just do good design, do good."
I wish I could put these three books into your hands.