Don't arrive more than 10 minutes early for an interview.

Being
too early is nearly as bad as being late for an interview.  Mentally,
it may not help you to be too early.  While you should arrive at the
place of the interview in plenty of time, only go to reception 10
minutes early.  Prior to that, go for a walk - you need to burn off any
nervous energy, and don't let it start to accumulate.  Avoid listening
to the radio, going to a coffee shop, checking emails, or other time
consuming, but counter-productive activities.  Instead, allow your mind
to settle and be clear.  If you really MUST do something, review your
notes on the company and the position and consider your answers.  Arrive
10 minutes early and get the job!