Stipulate the goals of your career and the reasons you prefer the position.
Create a Google Alert on the employer to know latest developments.
Interact, perhaps, with the firm's twitter profile.
Don't go off topic. Keep your brain on the things you are good at.
Be cautious to talk poorly about your workmates, boss or industry.
Do not be worried to say you don't know a response to questions.
Advice for Job-hunters:
"Examine yourself. A job search starts with you listing your character, enthusiasm, ingenuity, previous wins, know-how, and intention. How are you to find a job if you're not certain of what you wish to do and what you can offer a potential boss?"
It may be helpful to have:
Execute other ad-hoc duties as requested
A good team player as well as work on your own initiative
Be capable to create and grow good workplace relationships
Somebody who enjoys to 'get stuck in' and complete a mixture of jobs
Have a 'can do' attitude, prepared to help out the rest of the team in a constructive approach