EMOTION
I feel myself typing the same line over and over again "This piece is good, but it needs emotion!"
People in this world may claim that they are emotionless, but in reality everyone has emotions. Everyone is heartbroken when someone passes away, joyful when the MC concurs the climax, angry when things don't go as planned, and etc. But lately a lot of writers are missing the emotions in their writing.
Emotion is the key to a good reader/character relationship
You want your readers to relate to the character? Add emotion and describe it. Don't assume that everyone knows that the character is just happy!
It's as simple as that.
