You need to know why it closed. Don't take the initial answer they give you as the real answer, chances are they were struggling. Now that doesn't mean you will, but you do need to know how it was managed, who it really catered too and how broadly you can market yourself.
What you need to know -
Sales last 5 years
Rent, cost of goods, labor, seasonality. Hours, utility costs, insurance costs, licenses that are required.
You need to know how to hire, manage, pay wages taxes etc (or hire it done).
You need to know how to manage shrinkage (theft, by both employees and customers)
Ordering, not over or under ordering.
Dealing with customers.
Bouncing checks or use a service.
How much do you need to make, how much are you willing to work. Plan on at least 50-70 hours a week. You may only work 50 in the store, the remainder will be on paperwork.
If this doesn't scare you, then you are probably cut out to run your own business. Look at it carefully and then look again. I would also recommend talking to a Business Broker and looking at additional businesses so you can compare this one to others on the market.
If you want I will look over any numbers and give you my thoughts about what it could/should do. Last year I help a couple in Cincinnati buy a business and they are doing great!
Bought my own business