There is a lot that goes into SEO, from content, length of articles, the way your app is built, etc.

Good content is still king when it comes to SEO. If you are creating content that people are looking for, it will get indexed, and other publishers will link to your content (this is a big piece of the SEO puzzle).

Here are some best practices from Moz:
https://moz.com/blog/15-seo-best-practices-for-structuring-urls

Hope this helps!