Develop your ideas.
When writing a paragraph or writing an entire paper, it’s better to say one thing well rather than saying many things superficially.
If you focus on exploring just one or two main ideas, you are more likely to say something interesting. If you list a whole bunch of ideas one after another, you will probably not say anything about them that your reader hasn’t heard before.
Focus on a point and develop it. Build on it, make it go places. Take your reader on an intellectual journey.
“skate along the surface” (蜻蜓点水) by dividing your attention between many different ideas.