Personal development, gratitude...it's about 80% psychology and 20% mechanics regarding business success.  Logical, you have to deal with people in business and you first have to learn to communicate with yourself.
My personal help came from mentors, reading, self-communication, having a goal and writing it down and having belief in myself. 
Talk to yourself kindly, your brain picks up what you think and say to yourself which in turn has an impact on how you communicate with others and what you become.
Have a real passion for what you do, people pick up that energy/passion- remember, everything has an energy to it.
Be giving...put some deposit in your Karma bank. (doesn't have to be money). You get what you give.
Keep your word. Have some self-respect and be known for your integrity.