My first job interview!!!!

Hey guys!!! I've been going for a job since the beginning of the year and have finally heard something back! They're calling me in for a job interview tomorrow after school and I'm really nervous. I have no idea what to say and I feel like I'm going to screw up big time. Can you guys give me any tips? How I should dress? Any advice would be appreciated 😭 (it's for the deli if that helps)