With affiliate programs, you are in essence, providing a marketing service to other Internet marketers. In exchange for your services, you earn a commission for sales (or leads) that occur as a result of your marketing efforts.

Here is how affiliate marketing works:

You conduct an Internet search for affiliate programs that have products that are relative to the subject of your site. If your site is about competitive swimming, you want to promote affiliate products that compliment the subject.

When you find an appropriate affiliate program, sign up. Most affiliate programs are free to join. Once you have signed up, you will be issued an affiliate link (or banner) to promote on your website.

Your affiliate links and banners will have its own unique tracking code that will allow the company whos products you are promoting to keep track of your referrals, so they can credit you with any resulting sales.

There is usually some type of real-time automated email notification that you will receive whenever a commission is earned. If not, there is an affiliate back office where you can login to check your stats.

Just like with promoting your own products, digital products are usually better because they have a higher profit margin. Many Internet marketers payout 75 to 100% commissions; a small price to pay for acquiring a lifelong customer.

To find affiliate programs, you can search an affiliate program directory such as Clickbank or Commission Junction, where merchants are eagerly waiting for you to sign up to promote their products.
Another way of finding affiliate programs is to go to Google and type in your niche subject along with the keyword phrase affiliate program (example, archery affiliate program)