By Anshul Thakral

“Good mentorship is not one-size-fits-all.” That’s what David Brennan, former CEO of AstraZeneca, told my team during a GLG Institute event at our New York office last month. The GLG Institute is a membership-based community for leading executives that pairs its members with prominent chief executives, subject-matter experts, and policy leaders for direct mentorship and counsel. David, who is a GLG Institute faculty member, joined me in a discussion about the importance of mentorship and described his personal experience as both mentor and mentee.

David shared his views on the most important aspects of effective mentee-mentor dynamics and offered examples of mentoring relationships from his own career to illustrate his perspectives.

Here are four things that David Brennan taught us about mentorship:

Effective mentoring relationships are not one-size-fits-all. Mentoring requires open communication and mutual respect but does not have to fit into one particular mold. Although mentors can provide helpful advice on day-to-day tasks, David believes the most fruitful mentoring relationships center around broader discussions about professional development and career aspirations. In his experience, the best mentors guide rather than prescribe and create peer-to-peer dynamics. Valuable mentors ask thought-provoking questions and share advice from their own personal experiences to guide their mentees.

Preserving trust is crucial. Both mentor and mentee must commit to creating an honest, trusting, and appropriate relationship. Although mentees should trust their mentors to maintain their discussions as confidential, mentees must also understand the organizational and legal obligations that internal mentors face in terms of reporting to management. David discussed a particular situation in which a colleague trusted his mentor with information that the mentor felt obligated to share with his supervisor. The supervisor confronted the mentee and from that point on the mentoring relationship was permanently broken.

Mentoring should be a two-way street. The most successful mentor-mentee relationships involve equal effort on both sides. Mentees should invest time and effort learning about the interests and responsibilities of his or her mentor. Mentees will be most receptive to feedback and insight from their mentors if they understand their mentors’ backgrounds, schedules, and working style. When David was a mid-level manager, he worked with a mentor who had little time for conversation throughout the day. Instead, David would wait until the evening to catch up with him over coffee when the office was quiet. Through their informal conversations, David learned that his mentor read the Wall Street Journal every morning, cover to cover, noting ideas in the margins. David picked up the habit and passed it on to his own mentees later in his career.

Mentors have a responsibility to make the relationship successful. As the more experienced and often more senior party, mentors must make it clear that the relationship is a priority to them. For example, maintaining mentorship meetings as scheduled signifies to the mentee that he or she is an important part of the mentor’s priorities. Although mentees also have an obligation to be engaged participants, mentors should be prepared to drive the relationship by asking thoughtful questions and listening carefully to their mentees’ challenges.

In business, everyone searches to create the next big thing: the next Uber, the next Google. And as the world’s leading platform for professional learning and expertise, GLG pays a lot of attention to learning and sharing new strategies to improve mentorship. David’s reflections are an important reminder that sometimes the simplest approaches are the most effective. Mentorship does not have to be a complicated dynamic that sticks to a strict set of rules. Instead, in many cases all you need are two people interested in learning together.