1. The only way to know what will work for you is to write a lot - keep your head down and don't think too much about niches till you're published at least 50 articles.

2. Don't compare with others - we all grow at different rates. Focus instead on cracking the top publications and writing great stuff

3. Every niche can engage readers - virality depends less on the topic and more on the headline + presentation + writing quality.

But that said, articles that talk about wealth, health, and happiness - aka broad topics that a lot of people are interested in will do well.

If you have any more questions, shoot them in different responses so it's easier to keep track of them - and for others to see and benefit from the answers