What kind of business you want to get into? Franchising is more than running a restaurant or fast food. Franchise come in many different area of business.
Most money making or high profile franchise compay do not let you choose the location. They will offer you a location and that might not be your ideal choice. (Tim Hortons, Subway etc.)
You have to do a lot of homework, understanding the business, the competitors, the franchise agreement, cost structure, financing and options, what kind of training is involved, the last but no least, how can you get out of it. How to get out, what can you recover from the deal, how long will that take, can you resale the franchise, etc.
Talk to people in that franchise business as well as those who had been in that franchise, why they left?