If you’re planning on relying on SEO for traffic which most people do, it’s all about finding keywords where people would be interested in purchasing an affiliate product, and analyzing the competition of each of those keywords. Back when I was promoting Genesis themes, I saw hardly any articles about “Genesis eCommerce themes” (when I Googled it) which was a popular keyword. I got myself #1 for it. For SiteGround and StackPath, I saw opportunities to write articles on “settings” for each cache plugin (W3 Total Cache Settings, WP Fastest Cache Settings, WP Super Cache Settings, etc). After researching these keywords I was confident I could write better tutorials that the ones out there.
Then once you’ve got your domain name and hosting sorted out, it’s time to pick a CMS, or Content Management System, that will let you update pages, build your blog and integrate with all the other services you need. It’s hard to go wrong with WordPress—the CMS powering close to a quarter of the internet. Keep in mind that eventually as you start growing traffic to your blog, you'll be wise to invest in a managed WordPress hosting plan from a company with great service like Kinsta, where all of the settings are custom-tailored and optimized to work particularly well with WordPress-powered websites.