Job interview question help for 17 year old?

ive only had 2 job interviews, 1 at a job i wasn't able to get, and the other was a couple of weeks ago. The people from the one acouple of weeks ago called and want to set up a second job interview and i want to make sure i answer all of the questions in the right way.

When they ask what i can bring to the store to make it better, my mind kind of freezes. Mostly because i feel like i would be bragging about myself and bragging makes me feel uncomfortable. I know its not bragging but it feels like it to me. What kind of answers can i give? Im not looking for the "right" answer, just some good answers to give that will satisfy enough to hopefully get me a job.