Your introduction should always be a few sentences long, and should address the question directly. A good example of a question is 'How does Shakespeare present the theme of ambition in Macbeth?'For this question, you should start by using the words of the question and state how Shakespeare explores the given theme. An example of an opening sentence that does this is 'In 'Macbeth', Shakespeare presents the theme of ambition through his use of the characters of Macbeth and Lady Macbeth'. This is a good essay starter because it outlines your opinion and response to the question, but also indicates to the examiner that your paragraphs are going to be based around Macbeth and Lady Macbeth. To improve the introduction to your essay, try to include context. We know that 'Macbeth' was written by Shakespeare in 1606, so you can improve your introduction by using this information. For example, 'In 'Macbeth', which was written in 1606, Shakespeare explores the theme of ambition through his presentation of the characters of Macbeth and Lady Macbeth'.This provides you with a good opening sentence for an essay, whilst also ticking lots of AO's by including a clear response to the question, some context, and the use of the playwright's name.