Content should be original and creative in a way which is not redundant on anywhere outside the website. It creates a sense of exclusivity.
You could be an artist, a photographer, a poet/writer, a programmer/developer or a businessman. As long as your content provides some value to the users of this website you'll be voted.
An example of creative art. Follow 
Reputation is built over time. People notice your behavior and then judge you and categorize you into different types based on their maxim. So, you have to be careful what you post and how you communicate in comments and chat-boxes because all of that contributes in building your reputation. Remember, it's not easy to be seen and heard among a crowd unless your voice is valuable.
Back to topic, here's a list of topics that make it to the trending list every time.
1- Real-life story/confession (if it has a strong moral message)
2- Contest/games with reasonable prizes and recognition
3- Analysis/Statistics web-page depicting some data regarding steemit
4- Announcement of apps for platforms that lack it
5- If you're famous outside steemit just post an introduction and verify using your social media feed
6- You say
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All photos used in this post are cited from pixabay with CC0 license which don't require attribution.
