It's so easy to skip the self-assessment process, but it's a vital step in avoiding a huge investment mistake. Confirm in advance that you will enjoy the business you're researching--not making money at the business but the daily activity of the business: the customer service, the management of employees, the salesmanship, the details, the hours, the hard work. Keep those thoughts in mind as you proceed with your investigation. You will discover the nitty-gritty of the franchise as you dig deeper.
The franchisor will be your first and most convenient source of information. You'll receive a glossy brochure that stimulates the imagination but is usually light on information. Take the tour of the company's headquarters, make the rounds of company-owned or franchised stores in the area as part of the tour, and be inquisitive. Ask questions and take notes. Talk to all the people you meet. Ask them what they like about the organization.
Like any good detective, you should listen for clues about the company's style. What's the general attitude toward franchisees? Ask for details about the training program, and check out any training facilities at the headquarters. What system has the company set up for field support for franchises?