SEO for organic search: Search engine optimization (SEO) is a marketing tactic in its own right. Good SEO helps you craft post content targeting specific terms, called keywords, to rank high in the search results in Google and other search engines. This is something to understand and implement early to make the most of your content from day one. SEO is also why a narrow niche focus is best for most affiliate marketers. Targeting niche-specific keywords help you rank high in search results and be found by readers interested in your niche.
While your site is still new, it's a good idea to start capitalizing on someone else's audience. Continue focusing on building your own content, but also considering writing content for a few big, high-traffic blogs that are relevant for your niche. By writing content for a bigger site, you are able to get in front of another audience and showcase your expertise on a particular topic. This will eventually lead to more traffic to your site, as well.
The topic you choose must have enough depth that you can create a lot of content for it. This is important for building an authoritative site, for search engine optimization, and most importantly, for the end user. If you don't have enough content about a topic, you're not going to be taken very seriously as an authority on the topic and it's unlikely you can convince someone to make a purchase from you.