The main area in which the essay needs to be improved, as far as is immediately obvious, is need for a narrower, more provable thesis. While your four categories of claims about violence in the media seem to be probable, for an academic essay, you need to provide a narrow claim and specific, detailed factual evidence. Can you take one of these categories and think through what you are claiming in greater detail? For example, when you say "violence is everywhere", are you arguing that a certain percentage of people of a certain age and gender would agree with this statement? Or is it a claim about the percentage of scenes in specific types of media that are violent? If so, what are your criteria for calling something "violent"? What is your sample size? Your basis for sampling? You might consider a viewing diary that would enable you to claim, e.g., "10% of television programs shown between 10-11 pm on channel AAA in city BBB, during the month of October portrayed [certain types of violent behaviour]".