I wrote a blog for Interference Technology (https://interferencetechnology.com/what-is-the-number-one-item-that-causes-emc-problems-at-the-board-level/) concerning discussing issues to deal with in board level design, but emphasizing the number one issue, in my experience, that board designers need to worry about.  This issue is simple in concept, but not so simple in execution in many cases.  Something to think about.  Take a look and let me know what you think.