The Internet has made information gathering simple and easy, but sometimes the best information is found much closer to home, with real people, in real time.
Always take a look at other businesses similar to your own as a good first step. If you're looking at starting a new business, you may well be starting one similar to one you already know. If you're doing a plan for an existing business, you are even more likely to know the business well. Even so, you can still learn a lot by looking at other businesses.
Look at existing, similar businesses.
If you are planning a retail shoe store, for example, spend some time looking at existing retail shoe store businesses. Park across the street and count the customers that go into the store. Note how long they stay inside, and how many come out with boxes that look like purchased shoes. You can probably even count how many pairs of shoes each customer buys. Browse the store and look at prices. Look at several stores, including the discount shoe stores and department store shoe departments.
Find a similar business in another place.
If you are planning a local business, find a similar business far enough away that you won't compete. For the shoe store example, you would identify shoe stores in similar towns in other states. Call the owner, explain your purpose truthfully, and ask about the business.
Scan local newspapers for people selling a similar business.
Contact the broker and ask for as much information as possible. If you are thinking of creating a shoe store and you find one for sale, you should consider yourself a prospective buyer. Maybe buying the existing store is the best thing. Even if you don't buy, the information you gain will be very valuable. Why is the owner selling? Is there something wrong with the business? You can probably get detailed financial information.
Always shop the competition.
If you're in the restaurant business, patronize your competition once a month, rotating through different restaurants. If you own a shoe store, shop your competition once a month, and visit different stores.