And while some of the specific do’s and don'ts for CEOs are unique to their role, most essential things like setting expectations, developing a vision, establishing a management process, creating priorities, building your management team, and doing an exceptional job on your earliest projects apply equally to anyone in a new leadership role.

When Ron Daniel was the managing partner of McKinsey & Company from 1976 to 1988, he sent a memo to new recruits when they started, entitled, “On Becoming an Associate.” His advice is still memorable all these years later: “Recognize the necessity of getting off to a good start in the firm. Your first few engagements are critical. During these studies, you can establish an internal clientele for yourself - that is, by performing in an outstanding way, your reputation will be quickly established in your office and even the firm.” (We’ve incorporated Ron’s memo in the Appendix of the book.)

This is especially important because whenever you assume a new role, you’re in what Max DePree, former CEO of furniture company Herman Miller and author of Leadership Is an Art, calls “a temporary state of incompetence.” Even if you think you know a company - or a department or a division - before you take over its leadership, think again. As GE’s Immelt reminisces, “I worked for this place for twenty-one years before I got the CEO job and there were still things that shocked me when I took over.”

The knowledge gap is even wider for outsiders. “Anyone coming into a new situation is faced with the fact that they often have to do the most at a point they know the least. You may have previous experience and you may be smart and have insight into how things work, but you know the least about the actual company you’re engaged in at the same time you have to set things in motion,” says AOL chairman and CEO Jonathan F. Miller, himself recruited into the company from the outside.

We conducted a study that corroborated the importance of leading through influence. We examined individual assessments of the leadership capabilities of 235 candidates in 75 CEO succession processes that were conducted over the course of a decade. We then focused on the 47 CEOs selected out of that pool to lead public companies, which meant good data was available on company performance. Next, we examined correlations between leadership skills and company performance, as measured by shareholder return, operating margins, and revenue growth. This data was complemented by in-depth interviews with CEOs and candidates about their approach to leadership. Analysis of how different leadership styles matched with performance showed that the highest performers were the most accomplished in influencing through empowerment. This is not to say that the directive style of leadership is never appropriate. Some situations call for it, for example, crisis management. But, generally, the best results come from leading through empowering others.

Building on our study findings that CEOs who lead through influence were the most effective, we followed up by conducting interviews to learn about the development advice and training these leaders had received. We asked leaders to describe how they made the journey to becoming the highly effective leaders they were. What emerged is that a leader’s evolution generally proceeds in iterative cycles, with steps forward often followed by backsliding into old habits and then a renewed effort at change. It’s a process of trial and error, and often of fits and starts, as the daily grind of immediate demands diverts attention from one’s inner work. Those who continue to progress in the journey typically go through a three-phase cycle.

First, they are confronted with a necessity for change either because they took on a new challenge that reveals the shortfalls in their leadership or through feedback from their higher-up, colleagues, or mentor.

2. Launch

Indeed, in a recent global survey of 422 CEOs, 68 percent shared that they believed they hadn’t been fully prepared for the role. They believed they had the required strategy and operations skills, but the gap in their preparation lay in what they discovered is unique to the CEO role: how unexpectedly emotionally challenging it is and the great intellectual agility it requires. They had underestimated how different the job is from any other leadership role they’d had in ways that are profoundly disorienting in the early days.

Alternating between internal and external demands is only one way CEOs must learn to divide their time and energy. They also have to focus on the urgent here and now and on longer-term plans. In addition, they must be in command of the “hard stuff” of numbers and devote considerable time to the “soft stuff” of people management. Also crucial is striking a balance between taking decisive charge by quickly making some moves and engaging in learning more about the company. All require both/and thinking rather than either/or thinking. As skilled as leaders may have become in this over the course of their careers, the challenges of the Launch stage greatly up the ante on getting the balance right. Carol Tomé pulled off this balancing act with aplomb.