Let's talk about body language. Body language is basically what you have to say without saying anything at all. As I mentioned earlier, much of the impact you are going to have is based on your visual presentation. This is why it is very important that you greet the person with a warm smile and firm handshake. Also greeting the receptionist or the assistant with courtesy and respect is important, as this is the way you form your first impression.
Using a forceful voice, not too soft spoken is also very important as you want to sound confident and assure of yourself. Making eye contact with the person to look interested and to look confident in what you are saying and finally, your body posture, remember your body posture to always sit upright and look alert.