The essay conclusion must come in the final paragraph and should summarize all of the arguments (revealed using topic sentences) that were made in the essay. The point is to back up your thesis statement by summarizing all of the evidence presented within the essay and reinforce your overall argument.
Think of the essay conclusion as all of the facts condensed into one paragraph, from which conclusions about the essay matter can be drawn.
There is no real general structure for a conclusion - each will be unique but should nevertheless contain the points made above.
Writing the conclusion should not be too difficult as it is just a matter of condensing the main ideas you have already explained. It's generally said that if a writer cannot sum up their main points easily, then they do not have a clear understanding of their own thesis.
Make sure that the conclusion corresponds to the introduction of the essay - you need to restate the main idea once again without repeating the exact same phrase. The conclusion is meant to reinforce the issues you have just written about, and so you should adhere to the main idea that you wrote in the introduction of your essay. Should it be that the main idea of the essay has been altered while writing the main paragraphs, then the introduction should be reformulated.
Begin the essay conclusion by reminding readers of your thesis. This is the part of your essay where you need to emphasize your arguments and convince readers that the assertions you have made are correct and true, so you will need to go over each of the ideas you have made carefully. Bear in mind that the main idea of your thesis should be restated fairly often throughout the essay, before emphasizing your argument in the most compelling fashion in the conclusion.
You can reiterate certain points you have made by merging their ideas together so that they underpin and verify the argument you are making. The iterations should also tie-in together with your introduction. Consider the points you have suggested in the introduction; your proof of these points should be underlined in the most compelling way in the conclusion.
Uncompromising language should be used in the delivery of the essay conclusion. You need to write with an air of authority which cannot easily be contradicted. This can be achieved by using an authoritative tone of voice in the conclusion. For example, you could say that "It is quite clear that..." or "There is no doubt that this has been proven because..."
Remember also that you should never write in first person narrative in your essay conclusion.
Try to avoid using the word "conclude" or "conclusion", as this will make you sound less accomplished. Sentences such as "in conclusion then..." are not appropriate. It is better to attempt to use language which is more constructive, for example "We can see that there is a clear link between the industrial revolution and colonialism."
The key to writing an essay conclusion that is truly outstanding is to leave a lasting impact on the reader, which can be achieved through consistently restating certain points which you believe have been proved in the discourse of your essay. Finally, a powerful quote at the end of the conclusion can be highly effective in echoing the main points you have made.