They say leading engineers is like herding cats, I would not be surprised if this is a general truth of leadership, and the greater the size of organization, the tougher the job of leadership is.  Watching Obama is a great schooling on leadership.  In particular, his stimulus plan appears to consist of the things he wanted to do anyway but now they are aligned with the need to do a some sort of stimulus package.  This concept of alignment is a powerful one.   Books on selling your ideas tend to focus on the importance of executive time (the time of executives and management) and how quickly you need to make your pitch.  Thus a powerful key is to understand their goals and the goals of the organization and to align your ideas with it.  The stronger the alignment, the easier it should be to sell your idea.