Promoting affiliate products is still one of the most effective ways to make money from your blog. If you choose a trusted affiliate program that you know and love, and then promote it properly, you'll find that you can create a long-term (pretty) stable source of income.
Affiliate marketing is the process of earning a commission by promoting other people's (or company's) products. You find a product you like, promote it to others and earn a piece of the profit for each sale that you make.