Find products that offer an affiliate program. Check companies that list product owners with affiliate programs such as Clickbank.com, Neverblue.com or Commission Junction. Amazon.com has an affiliate program as well. Service providers such as web hosts, autoresponder distribution firms and review sites of consumer, professional and business products are other alternatives.
While your site is still new, it's a good idea to start capitalizing on someone else's audience. Continue focusing on building your own content, but also considering writing content for a few big, high-traffic blogs that are relevant for your niche. By writing content for a bigger site, you are able to get in front of another audience and showcase your expertise on a particular topic. This will eventually lead to more traffic to your site, as well.
Don’t just hope and pray that visitors will buy; setup everything correctly and make it happen! If you think that visitors will click on your affiliate links and buy just because you placed dozens of affiliate links on your website then you are wrong! You need to have a structured plan in place. Affiliate marketing is a business so you will have a much better chance of succeeding if you treat it like one.