Going to the affiliate network way, these are the most popular ones:

Amazon Associate: Sign up this program is quite natural because of the numerous product they offer; at least one of that product would flow with your audience, which will allow you to make sales and earn you a commission.The higher the number of transactions is a function of your commission.

CJ Affiliate: You can make your money signing up with this affiliate program, it was known as Commission Junction, you can try it out.

ShareASale: This a wonderful one also which you can leverage on.

Clickbank: You can promote their digital products, and this gives a very high commission compare to the tangible products.

with this affiliate you could achieve a commission as high as 80-90%, this is awesome!

e-junkie: This is another affiliate that specializes in digital products e.g., ebooks. This affiliate is excellent, and they offer a handsome commission.

Step 3: Get your affiliate links and add them to your site.

Immediately you get approved to become one of the affiliates for a specific company, you then get your link to be added on your site. To get it kick-off, you can replace the link of the products with that your affiliate links, and you can also add your new link within your content, or rather add affiliate banner ads to your website. Your site will accommodate all the affiliate programs you have registered with, and this program always has an affiliate manager you can call in case of any difficulties in locating and adding the links appropriately. Another better tactic you can use is to check any of your pages that have high traffic ten add your link to it and you place a call to action message, for example assuming you have an article on how to discover a better WordPress theme, the end of the post may be: 'Anytime you are searching for a better SEO-Optimized theme, I recommend one here'.