Think of body language like not playing with a pen, sitting upright, not slouching and speaking clearly.
Make it in time, to be chilled and ready for your interview.
Read up on the company, directors, and their history.
Don't worry by thinking of pessemistic happenings.
Suggestions for those looking for employment:
"Finding a suitable job is a job in itself. Arrange a plan of action and carry it out. Don’t just spend a hour or two a day and then give up. No business could stay in business if it were only open for a couple of hours a day. Think of it as a job."
It may be nice to have:
A strong determination to work hard, and develop in your role