yea. just khakis and dress shirt.
Nothing too fancy. It's just CompUSA. I remember wearing khakis with Tshirt for my Staples interview when I was 16. And I got hired.
Nothing too formal, just try to impress the boss with who you really are. Don't try too hard.
Firm handshake. Great greeting smile. Take your time while speaking, speak firmly with confidence and right speed.
good luck!