Career Steps: Tell what "you" are to the world

I was wondering when thousands of people are obtaining similar (professional) degrees, and developing more or less same skill sets,

• How one I be picked as best from the rest ?
• How can I show that I am different from the rest?
• How can I make it to the top cream?
• How do I know where am I standing in the skill/domain...?
  
• How do I show my expertise?
• ...
• ...
• ...

Well this how we should start thinking whenever we are about to apply for any job or looking to grow high in the career path.