Writing an essay on one of the argumentative essay topics requires to be well armed with strong and convincing arguments concerning one of the chosen topics for a argumentation essay. Your personal position and insight should of course be the basis of your work, but the main point is that your personal views have to be supported by founded arguments, reasons, proofs and evidences and proceed from the factual information.
The function of an argumentative essay is to show that your assertion (opinion, theory, hypothesis) about some phenomenon or phenomena is correct or more truthful than others'. The art of argumentation is not an easy skill to acquire. Many people might think that if one simply has an opinion, one can argue it successfully, and these folks are always surprised when others do not agree with them because their logic seems so correct.