Whether assuming control of a company or simply becoming a middle manager, employees often find the transition from follower to leader a difficult one. Great leaders are rarely born, rather they are created through rigorous trial and error. Great leaders grow into their roles and remain dedicated to their mission, regardless of the personal costs.
Sun Tzu and Machiavelli were the masters of leadership, and their philosophies, through their respective masterworks - The Art of War and The Prince, have taught generations of leaders the basics of being an effective leader, and their philosophies still hold true today in today's cutthroat top-tier corporate environment. Of their lessons, several are of paramount importance to today's aspiring leader.

First and foremost, consistency is the key to all leadership decisions. Setting the rules and abiding by them to the letter is the primary foundation for establishing an effective, time-tested leadership. Many managers have failed by either failing to abide by their own rules or by turning a blind eye on the indiscretions of favored employees. Once the rules are set, they must be enforced unflinchingly and with an iron fist. When consistency in punishments vanishes, then the credibility of the leader is compromised, and his or her effectiveness as a leader declines. When employees realize that even the leader is subject to the rules, then they will fall in line.

Machiavelli's immortal (and often reviled) phrase, "It is better to be feared than loved", is another pillar of effective leadership. While it is often the easier path to be friends with employees, it is hardly ever the effective path. Mixing personal relationships with leadership roles is often a fatal mistake that leaders make, and serve only to cloud judgment when an important decision - such as shedding inefficient employees - needs to be made. Managers who wish to avoid confrontations will also "butter up" their employees by downplaying transgressions, a poor leadership choice which often compromises the leader's managing power.

Sun Tzu's quote, "If troops lay siege to a walled city, their strength will be exhausted" is also of primary importance to effective leaders. Effective leaders do not waste their resources on unattainable goals. They set realistic goals and centralize priorities for employees. If your employees are "laying siege to a walled city" by either taking on too high of a workload or pursuing dead end projects, morale will plummet. According to Sun Tzu, high morale is the key to any leader's success.
Speaking of morale, the effective leader follows the military rule for commanders - the leader always knows the plan, even when he or she hasn't the faintest idea. You employees will look to you for all the answers, and if you reveal your frustrations or indecisiveness to them, they will lose respect for you and the company. It is extremely important to always assure your employees that you know what is in store for the company, despite your own personal reservations. Effective leaders also understand how to boost morale at appropriate times, without having such events appear contrived - such as company mixers or events.

Efficient meetings should also be a high priority for an aspiring leader. Companies often either hold too few or too many meetings. You need to find the correct frequency of meetings for your company, not so few as to cause mis-communication, but also not so many as to distract employees from their work. Clearly outlined, efficiently timed agendas that stay on topic are a pillar of good leadership. Employees who get too chatty during meetings with off-topic comments should be restrained, and setting a time limit in stone - for example, an hour - will make employees respect you more as an efficient leader who respects their time.

Finally, Machiavelli's motto, "The end justifies the means" should be the mantra of any effective corporate leader. As a leader of a company, your mission is to achieve the targets set by your company. For a large, publicly traded company, this is even more important, as shareholders can quickly sink your company's market cap if you fail to meet your projected earnings. As a leader, it is your duty to keep your eyes on the prize, making difficult decisions and sacrifices when necessary in order to attain the set goal. This is often a lonely path, but the path of a true leader is rarely one filled with friends.