To make money with affiliate programs you must:

-Choose one or more merchant to affiliate with.

-Create contextual content to the products you want to “sell”.

-Bring potential customers to your web pages (via placement in search engines, buying ads, etc. ..)

Choosing merchant.

Merchants are thousands, each offers at least one product / service and many offer tens of thousands. So the choice is plentiful, the important thing is to choose well.
Factors to consider are:
1)  Quality of site-merchant.
Do you buying on that site? Has discount prices or, alternatively, products difficult to find elsewhere?
It ‘a famous site / brand? If you answered yes to all (or most) of these questions go to step 2.

2) Type of products / services. Users of your site may be interested in some products sold by the merchant? You can create content on those products? If you wish to purchase advertising on search engines quickly assess how much competition there is (a more detailed analysis can be done at a later time).
3)  How It pay? Estimate when you can earn for each sale is essential if you are considering buying advertising on search engines.
4) The merchant uses cookies to store the provenance of the customer? The merchant must assign the sales commission even if the customers buy many days (or months) after clicking the link on your site. Merchants who do not use cookies are to be avoided.

continue…