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. 
Take good pictures. Some of the options below don’t require you to actually take the picture and sell the product, but for the ones that do, make sure you take a clear picture that makes your product stand out from the others. If you’re going to be taking a lot of pictures, set up a small “studio-like” area in your home with a backdrop and proper lighting to really make your pictures come across as professional. And of course, you’ll want a good camera too.
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.
Who doesn’t want to earn more money? Whether it’s through part-time jobs or freelance work, adding more dollars to your cash flow every month is always nice. But unfortunately, not everyone has the time to pick up another job or do additional work on the side. If that’s the case for you, don’t give up. Instead, turn to the one thing you probably spend a majority of your time on: the internet.
Write pitches. If you have located a client for whom you want to write, send pitches, which are topic ideas for articles. Write pitches that not only show your expertise, but also demonstrate your enthusiasm for the topic. First, read the publication to which you are sending pitches to familiarize yourself with what they publish. If applicable, identify a specific section and send our pitch to the appropriate editor. Also, include a brief summary of who you are.
When I used to write product reviews, I used to include just one affiliate link. For some reason, I thought that a single link would be enough and I didn’t want to run the risk of annoying readers with more links. However, one day it struck me that the reviews I was writing were quite long and by the time people got to the end of them, the link to Amazon was no longer visible.
In the past, large affiliates were the mainstay, as catch-all coupon and media sites gave traffic to hundreds or thousands of advertisers. This is not so much the case anymore. With consumers using long-tail keywords and searching for very specific products and services, influencers can leverage their hyper-focused niche for affiliate marketing success. Influencers may not send advertisers huge amounts of traffic, but the audience they do send is credible, targeted, and has higher conversion rates.
I have a free WordPress website with 1000-2000 visitors/month. I was trying to place Amazon Affiliate ad links last night and failed/flailed mightily. I would paste the links into my posts in the HTML mode, switch to Visual mode, and could see the image. However, every time I tried to save or update the post, the image reverted to the gangly hyperlink. As some suggested, I tried cleaning the links of any formatting from the copy and paste with text edit. No dice.