1. Respect Each Other
First step of the process is to have a respectful environment. Starting with the CEO or President, the company need to respect the differences between the members of the firm. Respect is the stepping stone to a better culture. In this step I see firms that have their own diverse organization or affiliated groups. Here is where firms try to build a pipeline of diverse candidates using their current respectful culture to attract them. In certain cases, the firm will try to 'train' that diverse candidate in the ways of the firm.
2. Understand the Differences
When members of the firm are respectful they can start the path of trying to understand their differences. This step is more difficult to accomplish that what it seems. If you believe your firm has accomplish this step you are probably in the first step. Understanding the differences require a change in processes. Your believe that 'your way is the right way' has to change. There is a reason why the world doesn't operate the same way. If you still believe that your part of the world has it all figured out that is probably a sign of not being there yet. Those processes that change are not only related to recruiting, they are probably 75-85% of all your processes including but not limited to recruiting, training, retaining, promotion, and operation.
3. Cherish the Differences
By knowing that there are different and sometime 'better' ways to operate an entity, your firm can take advantage of these differences. Firms that have changed their processes to become more diverse are now empowered to cherish their differences. Firms that have accomplish this step can use their culture to be more adaptive/responsive to/of client's need. Those firms would probably enjoy of more innovative ideas and have a better chance of solving the next generation of problems.