I used to work at a local ma and pa grocery store, but it eventually closed down due to no business. Just do as your told. They pay you, so do what they want and how they want it done. I started when I was 14 and it closed down when I turned 17. Because I did as they wished, how they wished, and didn't slack off I got 6 raises. Started at $6.50/hour and ended at $9.75/hour. Not only that, they're GREAT for references. My new job is at a somewhat large American corporation called Kroger. The first thing the interviewer said when I sat down was, "So I called your previous boss and he told me nothing but good things about you."
Point is, don't slack off, do your job, and always come to work unless you're deathly ill. Don't be lazy.