Time-flexibility.
My manager was nice about how he constructed the weekly schedules. If I wanted a thirty-hour week, I'd get one; the same goes for a forty-hour week. Not every week was perfect, but I took advantage of this flexibility.
What I wish was different
The staff.
Many of the employees consisted of lazy college kids. There were many times where I was the only one, besides the manager, to take matters seriously. Nothing was done to combat the problem.
Advice
Learn about the product.
It's rather funny that I chose to work at a beer store although I know next-to-nothing about beer. I had to adapt quickly to different products (domestic, craft, creation) to properly service my customers.