A common theme I have experienced across the arts is that whilst there is a will and a concerted effort to attract more diverse candidates, retention remains low.
My best piece of advice is to read this article called 'The 'Problem' Women of Colour in the Workplace. It contains a very clear diagram that explains why this is a recurring theme. When I first saw this diagram, the systematic exclusion that I had faced working in the arts was, for the first time, drawn out clearly. This is when I understood that culture is the most important part of a job for me. Reading this article is the first step. I can work with you to create a culture that supports diversity long term in your work force.