You can use affiliate links after the fact. You don’t have to decide upon building a WordPress site that you’re going to optimize it with Amazon affiliate links. You can decide down the road that you want to give affiliate marketing a try and, consequently, revisit old content, embed affiliate links within it, and start generating revenue that way--especially if your old content is finally starting to take off.
There are many ways to get people onto your list. Lead magnets are one such resource. For example, you can build ebooks, checklists and cheat sheets. But you can also do content upgrades, such as PDF versions of an article with added resources in them, four-part video training series, and more. Think about your audience and what you can offer them to better serve them, then treat them with some respect and you'll eventually reap the rewards.
Recent corporate changes and folding 2Checkout into a larger company that is involved in payment processing and e-commerce means that the affiliate program can sometimes feel somewhat neglected. But the ability to generate custom coupon codes and the comprehensive knowledge base make 2Checkout a good option for experienced affiliates with an established user base. But if you’re just entering the affiliate field for the first time, 2Checkout might not be where you want to start.
Set up a website. Professional or business websites can also use the Affiliate program. However, they are best used with people who do not sell similar products on their website, since Amazon's marketplace can drive business away. If you have a website promoting different products, a club, a non-profit or a service, then you can recommend quality products on your site and make money doing it.