How can you prepare yourself to become an effective manager in an increasingly uncertain and global business environment?
There is no simple way to do this. Many of the attributes needed may well be innate to people rather than things that they can learn.
The main thing that a manager needs to be able to do is to be flexible. As you say, the business environment today is uncertain, which means that it is likely to change at any time. In such a climate, managers need to be able to easily throw off old ideas about how things work to embrace new realities. Managers in today's world also need to be flexible because they may well be working with people from different cultures who have different attitudes and expectations. This is another situation in which flexibility is key.