Q: Be clear about the money. Ask 'where is the money?'
A: Be certain about this if you plan to join an affiliate program. Plan to be in control of your earnings. Be on guard if you can't. There are many affiliate programs that you will encounter in your research that offer 'the most exciting' opportunities to make money online. Look at who controls the money and how they do it. Most often, you will depend on their good nature to reward you. There are many sad stories of vendors concocting reasons (usually based on something in the fine print) about why they will not pay you. Often there is no recourse against them. There are others that are more honest an upfront like Google in its Adsense program, although there are complaints from many about how much Google actually is willing to reveal. If you can do it, be in control of your money. There is nothing more frustrating than losing out on your well-intentioned efforts to some scheming clause in the vendor's terms.