We can help you improve essay by editing and giving ideas to polish it further. However, you need to work out your draft and post it here. On this topic, you can do a real good job if you really put effort. You first have to research to find facts about Mr Mandela's life, the leadership he provided to ANC for fighting against apartheid policy etc. If you google you can find various sources that provide lots of information about this great statesman of this century. As for the structure, you can introduce who Mr Mandela is in the introduction by telling very briefly about him and his background (only main points) Then move to the body paras to highlight each of the special points that you intend to discuss. Dedicate one body para for one such point. Finally conclude your essay, by saying what sort of impression Mr Mandela has made to the world and how worthy it is... These are just my suggestions and you can do it in your own style.