Accelerating the New Manager's Start
The transition from contributor to manager is very difficult for many individuals to make, and it would behoove senior managers to pay close attention to getting these individuals off to a good start, both for altruistic motives (to ensure that there will be competent leaders to take over after they retire) as well as personal ones (to make sure that they don't screw up so bad that senior management is unable to repair the damage).
Additionally, recent research suggests that the lower middle levels of management play a far more crucial role in the company's success than previously believed - they are not merely layers of middlemen who contribute nothing to the organization except a conductive buffer between the top executives and the front-line workers. (EN: Not to cast aspersion, but I do wish he'd have cited his sources of this information).
One of the key tasks a new manager must face is accumulating informal power. Generally, they are quite good at looking after their direct subordinates, but neglect to develop relationships with those whose assistance they will need, but over whom they have no direct control.
There is also a profound shift from the role of a person who personally performs tasks and one who gets things done through others. New managers need guidance in helping them delegate - not merely in delegating responsibility, but also in delegating authority
The development of trust is key: the relationship of a manager to his subordinates is influenced by his relationship with his own manager. There are going to be a lot of missteps, and it will require coaching and mentoring to get them on their feet - but at the same time, they need to be given autonomy, even at the cost of making mistakes.
In time, a manager should begin to take charge of his own development: to find mentors, coaches, and supporters other than his direct supervisor; to seek out opportunities for formal and informal training. This requires a careful balance, such that you can encourage the new manager to be more proactive in developing himself without seeming to suggest that the "need" for development is a weakness.
Organizations that do not presently do a sufficient job of training and mentoring their new managers are going to have difficulty getting themselves into shape, as the current managers have no experience with being mentored, and will struggle to act as mentors to others. But once it takes root, the vicious circle works in your favor: well-trained managers become better trainers, and it becomes a cycle of improvement.