It depends what sort of essay you have to write. There are different tips for the following essays; creative, informative, argumentative/persuasive. However you must brainstorm your topic first or create a mindmap. Overall, proof reading & editing are most important. Also don't forget to use the spell check function on your computer.Make sure that your paragraphs flow easily by using linking words eg futhermore, however, similarly, comparitively, on the otherhand etc. In your concluding paragraph never write, 'in conclusion' as that is stating the obvious. Include a bibliography on the last page if you consulted any sources.