I think being really proactive in your mindset, open to all opportunities to learn from others who have come before you in leadership positions, not being afraid to ask questions and possibly finding a real-life mentor would do more for you than most tapes and seminars.
But I recommend anything by Denis Waitley.
Go to
Do something, Learn something, Share something, Change something - Meetup.com and type "mentor" into the search field....
Jennifer