Do Your Homework.
You wouldn’t buy a car without researching the brand, make, and model a bit first, would you?
Then why would you go to an interview without first doing a Google search on the company, looking at their website, and studying what they do?
It’s easier than ever these days to not only research the company, but also the person interviewing you — and you may even be able to find out the salary range for your position at that company!