Tabish there are couple of things you need to look for, when you are promoting any product on the internet. There are two dimensions of looking product:
1. From Affiliate Point of view
2. From People Point of veiw
1. From Affiliate Point of View
First of all you need to check what interest you most, if this thing which you feel interest you, then you can promote it, then you should check a few aspects of a product, like, you should first of all check earning per sale, how much will you earn on every sale you make,then you should check for the conversion rate or % of that product, if a product has a conversion rate of 3% suppose, it means 3 out of every 100 visitors to that product's sales page buy the product and finally you should check is rank of the product and reputation of the merchant. (please do view the sales pitch page and read it fully, if you feel like buying that product, only then promote that product!)
2. From People Point of Veiw
In this are you should look, do people really need this product? get yourself in your potential customer's shoes and then think what a consumer would feel about it? would they buy that product if they are somehow taken to the sales page of that product? how would you feel if you need the same kind of cure? or product?, then how would you search for that product? if on internet what "Keyword" you will type in search engine to find that product? remember, keyword is the game changer for any product, if you chose a wrong keyword, i bet you can never make the people buy your product. Just remember how bad you feel when you search for a free software and in the end before clicking the download button you find, "Sir you have to pay just $5 for this download

" doesn't it really get you then? So you should be fair enough with people, tell them somehow that they will have to pay for this product.
Thats all i had to say!! Good Luck!!
