As a first step, you could start a blog (free from blogger.com) on a topic that you are interested about and publish useful content. At some point of time (once you are getting some traffic) you could monetize that blog for income. But this takes time to pick up depending on the topic and the level of competition.
For instant earnings, you could join clickbank, select some products and promote them using Google Adwords (but you have to pay money for advertising).