Don't be scared to say you don't know the response to questions. Don't lie.
Consider your answers. You shouldn't feel pressure to answer rapidly.
Create a Google Alert about the employer to keep informed.
Job Hunting Tips:
"Before you have the interview find about the employer. Get to know what the firm does, who their competitors are, and their principles. An interviewer will not listen to what you say if you don't understand how they do things."
Some useful things would be:
Good levels of literacy and numeracy and a 'find a way' attitude
Commercial experience in a sales environment
Ability to multi-task prioritises work, demonstrate accuracy and pay attention to detail, meet deadlines
Be independent, ambitious and innovative
A high level of IT skills to include MS Excel and PowerPoint