I just read this article from Marshall Goldsmith's book "Mojo ...". It is an excellent book and this paragraph sums up a couple of important points. Read it and learn from it.
"Every decision in the world is made by the person who has the power to make that decision - not the "right" person, or the "smartest" person, or the "most qualified" person, and in most cases not you. If you influence this decision maker, you will make a positive difference. If you do not influence this person, you will not make a positive difference. Make peace with this. You will have a better life! And, you will make more of a positive difference in your organization and you will be happier."
This approach sounds simple doesn't it. But it is certainly not easy! Treat your decision makers like they are your best customers.