Make a good first impression, offer warm greetings with all you speak to. Stand up, make a smile, keep eye contact.
Do not merely read through your CV. An interview is an opportunity to present all of the skills you have that your CV can not communicate.
Make sure your recent twitter posts are positive.
Don't go off topic. Keep your brain on the things you are good at.
Never be late. Plan for delays.
Try not to oversell who you are.
Create a Google Alert on the employer to know latest developments.
Advice for Job-hunters:
"Read a paper or relevant blog that writes about the niche you're looking for a job in. This will make sure that you're up to date about movements in the field and will also be useful in an interview and shows the possible company that you have taken the time do so."