Essay writing: respect the craft.
The University of Melbourne has produced an excellent handout detailing the importance of introductions and conclusions in the structure of your essay. There are examples and diagrams to look at. In essence, these elements need to be concise and plainly expressed; they are not a chance to use the thesaurus liberally at the expense of your reader’s comprehension. Read the University of Melbourne’s two-page guide to writing introductions and conclusions here: writing_introductions_and_conclusions_for_essays_update_051112