Steemit Content:
If you good at sports,you should write about sports news.
I think who is expert in their respective fields,they should choose that topic to write on steemit.
Continuously Changing topics:
Like me, most other writers feel that,they basically lack content or quality contents everyday.
Don't worry about that,Just put on importance over daily changing topics such as cryptocurrency news or national news and make enriched article every day.
My advice:
Try to write at least 3 contents in a day.
because 3 posts can generally enough for an individual to get quality and standard.