There is a lot of information available on the Internet about most franchise opportunities, so you can get a pretty good idea of whether you are interested before you even talk to a sales person. It is always a good idea to prepare a list of questions you have before you contact the company. That can help ensure that the conversation will follow the direction of most interest to you.
Also keep in mind that what you are trying to find in a franchise is a good match with not only the opportunity but also with the people at the franchise company. If you find that they are pressuring you or not being responsive to your requests for information, it is probably a good clue that this isn't the right franchise for you.
When you talk to your peers who are owners, ask them for some references to friendly and helpful staff at the franchise company that you can talk to. You'll never get a franchise of your own until you start talking to the franchisor, but you'll find in most cases that this is a pleasant and informative endeavor and not at all threatening.