Generally, your essay needs to have three main parts: introduction, main body and conclusion.
In the introduction, you must be careful to formulate the thesis that you intend to develop. In the main body, you present the arguments that support your thesis. In the conclusion, you reiterate the thesis and expose some of its possible general effects: what aspects of the society could be affected by the ideas you have demonstrated in the essay?
When writing a good essay, your main purpose is to persuade the reader that the ideas presented in your work are true. You can achieve this only if the arguments you bring in order to prove your thesis are logical and convincing.