a lot of comments here suggested focusing on style (use a thesaurus, by the way), and that's all well and good, but good writing flows from thoughtful reflection. it's about digging deeper into the material you want to comment on and trying to weave a narrative with threads of experience that are unique to you. you don't need flowery language, really. you need interesting thoughts.

how do you get interesting thoughts? some people have suggested reading, and that's a good way. but also try to have life experiences outside the norm. spend time with people you don't feel entirely comfortable with. try to understand their lives. go places that feel slightly dangerous. ask 'why?' expose yourself to a diversity of ideas. study topics that really interest you.

let these things inform your viewpoint. pull such perspectives from the far reaches of your brain and mold them to fit the topic at hand. sometimes it turns into an engaging comment, and other times, not so much. don't worry about these latter cases.

and choose what you comment on based on how uniquely you can add to the discussion.