There are a number of interview success tips that should go without saying. But even a brief conversation with anyone who's ever conducted interviews will reveal that not everyone's read the memo on basic interview etiquette and the importance of making good first impressions.
Arrive on time. Being early is acceptable, as long as you don't beat the receptionist to the office. Arriving ten minutes early prevents you from appearing overly eager.
Dress appropriately. Nothing says more about a person's attitude than the care with which they present themselves, which means that frayed jeans and miniskirts are out. Be careful not to overdress, either. Perform an incognito drive-by of the facilities at quitting time to get an idea of the company's dress code.
Make eye contact. It's imperative to be fully engaged during your interview, and this is rarely accomplished by averting your eyes. A disinterested interviewee makes for a disinterested interviewer.