With the ability to rank organically in search engine queries, bloggers excel at increasing a seller’s conversions. The blogger samples the product or service and then writes a comprehensive review that promotes the brand in a compelling way, driving traffic back to the seller’s site. The blogger is awarded for his or her influence spreading the word about the value of the product, helping to improve the seller’s sales.
Find a profitable niche. Starting with your interests, write down as many niche ideas as you can. Think about topics people might search online. Ideas include passions (like surfing or body building), fears (like spiders or speaking in front of crowds) and problems (like getting out of debt). Do keyword research to see it others are interested in the topic. Find out if a domain name is available that matches the keyword 100 percent. 
This is one of those businesses where the time you spend is directly related to how much you earn. It typically takes about 1 or 2 hours to create an Amazon affiliate website or blog. One website or blog can earn anywhere from $10 to a few hundred dollars, or even $1000 or more per month. The key to making more money is to have more than one website. Some of the largest professional Amazon affiliates –the ones who make a six-figure income, have dozens of these sites. But the average guy or gal like us probably has anywhere from three to ten.
In my experience, it’s product-related blogs that tend to do best with Amazon. Most blogs probably have at least some possibilities (for example here on ProBlogger I occasionally link to a book that relates or a computer or electronic tool that I think might be useful to bloggers) but the reality is that this blog will never convert as well on Amazon as my photography site.
Get samples. When you first start out as a freelance writer, it can be hard to get work without any published samples. However, it is possible to get quality samples if you are willing to do some writing for free. First, you can publish content on your own blog or website. Also, you can write guest posts for someone else’s blog. Finally, you can write blog posts for free in exchange for a byline.
Set reasonable expectations for earnings. You've only invested $20. You're going to make 5 percent on most products. That means that you need to sell $400 worth of stuff to make back your investment. You get credit for purchases customers make while at Amazon besides just the product you linked to, so it's not as hard as it may sound. It won't make you rich, but it's not hard to be profitable, and the income builds over time.
No matter how good your marketing skills are, you’ll make less money on a bad product than you will on a valuable one. Take the time to study the demand for a product before promoting it. Make sure to research the seller with care before teaming up. Your time is worth a lot, and you want to be sure you’re spending it on a product that is profitable and a seller you can believe in.