In trying to develop one's leadership capabilities, you often hear comments like "get a consultant", "you could use a coach," or "find a mentor." It's a bit confusing on what are the differences among them. Having discovered that, next comes the basic question of what are your needs? What would help best, or do you even need one? These fundamental questions rest with your situation, but hopefully herein lies some help on eliminating the confusion.
Having been an executive professor, there is another option that grounds the other three and worth discussing first, a teacher. There is a great body of knowledge on leadership from academicians and practitioners. Teachers educate by imparting this knowledge, particularly those concepts from leadership scholars, to help raise your leadership awareness and competency. Business courses certainly can help one run a business. Leadership courses as part of that curriculum can be beneficial in providing specific knowledge not previously possessed. Of course, going back to school and perhaps getting an MBA is not always practical.
Running a business presents many challenges, some more impactful than others where you want to really have thought it through. In other cases, specific issue area arise where you just lack the expertise in solving or developing solutions. This is where consultants can play a role. They bring their expertise to help diagnose the challenge, recommend solutions, and in certain cases help implement the solution. In Shell, I found consultants could be useful particularly because they better understood some of the competitive dynamics since they consulted with my competitors too! Like a teacher with a specific course, consultants generally have a defined project, and so they come and go.
The International Coaching Federation defines professional coaching "as partnering with clients in a thought-provoking and creative process that inspires them to maximize their personal and professional potential, which is particularly important in today's uncertain and complex environment." They go on to say that "Professional coaching focuses on setting goals, creating outcomes, and managing personal change." Coaching attempts to draw out the best in the leader through various processes including assessments, careful listening and exploratory questions, and so forth to help clients clarify their direction and stretch their capacity to lead and influence. The modus operandi of coaching is amenable to training, and many coaches become certified. Coaching relationship can last for some extended time.
Mentors in principle provide wise sage advice because they have been there and done that. They may have started and led their own company, been a senior executive in large corporations, or in any event have some wisdom that helps the client grow. Like coaches, mentors establish a longer term bond to enable their clients to fulfill their objectives by a variety of means depending on their background and experience. Mentors like the Silver Fox Advisors often engage in understanding the whole individual by exploring and helping to develop their personal purpose. Mentor's processes can be wide ranging. For example in my case, I teach the client about leadership, provide consultant like advise on major challenges, use coaching techniques to help bring out their best, offer my experiences on various client problems, and engage with them on developing and fulfilling their personal purpose. So mentors can be harder to precisely define. If you are seeking a mentor, look for one that you can really bond with and understands your needs.