You can earn commission on every sale made by simply reffering and recommending the products of other companies.The best way to start is by finding a website that has a wide range of affiliate products.

The best way to have success with this method is to have your own website/blog where can you promote the products by writing reviews,  by simply  adding  a banner ad on your website or just promoting the affiliate link through manual traffic exchange websites.

Also to have guaranteed success you have to provide great  , original and  interesting articles, reviews of the products  that can capture the attention  of the visitors and convert in buyers.

There are many websites that are offering affiliate programs and the most known and used are Amazon and Clickbank.