"People are more likely to end a negotiation positively if they like the way you present yourself." Yes, I fully agree. First and foremost, present yourself as a clean, well groomed person. Remember, the first seven seconds are the most important. Whatever you say and present afterwards, will be influenced by your first impression of whoever is interviewing you. In other words: Start with the way you look to effect what you say in your interview.
That is true. At the same time, your rhetoric is as important. Philosophers are usually very unkempt...