Ray asked a question:
What must the US do to tweak her foreign, strategic and economic policies, given the unfolding circumstances, to be able to dictate the 'fate' of the world as she is still doing?
I am not convinced the USA has ever been able to dictate the 'fate' of the world as she is still doing.

There have been a few times when the USA has been the paramount capable nation, after WW1 & WW2 for example. It has not always used that capability, often due to domestic factors and more recently has been obsessed with terrorism to the detriment of many other issues - including its own problems at home.

The USA would have to do far more than 'tweak' its policies to attain the position you ascribe to it - dictating the world's fate.