"I do the very best I know how - the very best I can; and mean to keep doing so until the end. If the end brings me out all right, what is said against me won't amount to anything."
Regarding the subject matter of business, I have always stressed to my colleagues that everything boils down to buying and selling. In every human contact, you are either selling or being sold on a product, service or idea. Think about it.
The law of association states that you are the average of the people you associate with the most. If you constantly associate with successful business people, you are very likely to be a business success. If you hang with illegal drug dealers, even if you do not deal drugs, you will attain the mindset of a drug dealer and will eventually become one.