Before you become involved in any program, most important thing you can do is research. Learn and think about product. Is it something you could benefit from personally? Could you see yourself recommending it to a friend or family member?
Do your homework and find out as much about program and people that run it as you can. Get a feel for operation and see if it will be a good fit. You want to find out exactly what you'll be becoming a part of as this will save you some time and discouragement in future.
As you pick your program, you need to be aware that in order to expect to make any profit, product or service needs to be one that appeals to a lot of people. It has to be one that you feel confident putting your name on. Your name is your reputation and you have every right to be picky.
Does this program provide you with sales material and training support? If your sponsor is not active in training you, do they offer option of being placed with another one? It will ultimately be your decision how much time and effort you're going to spend developing yourself and your program, but does program offer tools to help you succeed?
Make sure program is everything they tell you it is. Many people are charmed into signing up for something and then being left to wonder what to do next. They aren't trained on how to sell, who to sell to and fact that their payoff is related to their participation.