You don’t necessarily have to have a huge site or lots of traffic. Consider emailing an affiliate program’s contact person (look for contact info on the site or in affiliate newsletters) if you send a lot of leads their way, rank well in the search engines for a related keyword or have a high conversion rate. Make your email compelling. Read my tips here. You just have to be a good fit and provide excellent value to the merchant. Another good resource for this is here.
It will probably take a couple years to build a sustainable, passive income. That is the 1st car I have EVER purchased myself at age 29 (I was broke until then and leased from my parents). But the time committed to affiliate marketing and creating great tutorials and YouTube videos was worth it… I work for myself, there is virtually no limit on how much I can make, my schedule is flexible, and I collect enough passive income to live how I want.
Choose an affiliate program. First, you must decide which affiliate program to join. Affiliate programs often have a theme, such as gardening or weight loss, and you should find a theme that interests you. Look for a network with a lot of product codes that are relevant to your topic. Consider networks like Commission Junction, LinkShare, ShareaSale, Clickbank, and Amazon. Remember, it isn't really about the network – it's about whether the network is relevant to the content of your website.

The problem with affiliate marketing, like many other home business options, are the so-called gurus and get-rich-quick programs that suggest affiliate marketing can be done fast and with little effort. Odds are you've read claims of affiliate marketing programs that say you can make hundreds of thousands of dollars a month doing almost nothing ("Three clicks to rich!"). Or, they suggest you can set up your affiliate site, and then forget it, except to check your bank deposits.