Creating successful (you define what this means) content online, no matter the topic or audience, is dependent upon research. Use online tools such as Google Trends, Google Suggested Search, Keyword Planner, etc., to discover what people are searching for. You can then use this data to create "buyer personas" - which allow you to build profiles of the different types of people that you want to consume your content. Once your buyer personas are accomplished, you can assign specific keywords and phrases to each and begin writing. If you're interested in learning the details of each, along with the next steps, I'd be happy to help! Good luck!