My Grandmother once told me:

"If you want to work at a company, dress like the people that work there. Because those are the people that the company hires."

I've used this general philosophy in my life to pass courses at university, win competitions, and get through job interviews. I don't know if my grandmother meant this in a literal sense, or was hinting at the fact that (as Tony Robbins says) success leaves clues. When you understand what people are looking for, the game becomes a lot easier - you simply need to mould yourself and your communication to fit a winning persona.