If you're serious about making money online, start a blog. Blogging is one of the easiest and most sustainable income sources. As long as the blog is setup the right way, in the right niche, with the right content targeted at the right audience, and the offer is complementary to the content, you could make a tremendous amount of passive income from a blog.
Bad product picks could hurt your brand. Chances are good that if you’re including an affiliate link in your content, then you’re willing to put your full support behind the product. However, if the reputation of that product should sour with the public and you fail to catch it, that recommendation of an untrustworthy product could hurt your brand.
Etsy: While Etsy's popularity has declined recently, it's still a great resource for selling handmade items online. No need for complex ecommerce sites or merchant accounts or any sort of automation. The company takes a commission of every sale and charges a small listing fee per item. But many still use Etsy as their primary source of income. The best part is that you can also sell digital products on here such as poster designs.
If you're interested in online marketing, setup email software and create a lead magnet that you can use in your sales funnel. Then, build up that list. It's often said that you can expect to earn about $1 per subscriber per month. If you have a list of 10,000 subscribers, that means you can earn roughly around $10,000 per month. You will need to deliver value and not pitch them on every email, but it is a very achievable goal in a short period.
Analytics are limited. Unlike with conversions made directly on your WordPress site, you’ll be limited in terms of what you can learn about the people making purchases through your affiliate links. While Amazon does provide you with details about clicks and sales, you won’t get deep insights into who the consumer was and what they did on your site before they got to that point that you would with Google Analytics.