The first thing that will be important for you to do is pick a niche that you feel comfortable creating regular content in; a lot of people make the mistake of starting an affiliate marketing site in whatever niche they expect will "make the most money," without realizing that the real niche that will make the most money is whatever niche they are able to do a good job writing about and exploring, in order to create a truly valuable website.
After you have selected a niche that is right for you and have set up your website to go along with it, it will be important that you start learning about search engine optimization in order to bring extra traffic to your site; by learning about and applying SEO, you can zoom to the top of search engine rankings pages, and can create a lot more exposure for yourself.
And finally, realize that a lot of people stop at SEO - but when you take things one step further and actually go to where the people are, you will greatly increase the likelihood of success on your site. This means that you should constantly be on the lookout for blogs and forums that are similar to yours, and should use these as places where you can interact with others, and you should build a social media presence that will enable you to come in contact with lots of people you do not yet know; by combining this with the right niche for you and good SEO work, you will be able to start making some serious money online, and will be able to move toward the life of your dreams.
The REAL online passive income?: