How do I write a good introduction?

Your introduction doesn't need to be revolutionary - all it needs to do is tell me your argument. As a marker, I want your argument summarised for me so that I can look for it when I read the rest of your essay and give you marks more easily. It should be 3-5 sentences telling me briefly and clearly what you're going to say. The first sentence should clearly answer the question; if the question is "The lovers are the only source of hope in The Tempest. Discuss." your first sentence should be something like "The lovers are the only symbols of hope in the corrupt world of the nobles in The Tempest" - that tells me clearly what you think. Then your next few sentences should tell me in short how the author shows this - really a summary of what's going to be in your paragraphs. So if your first paragraph is going to be about a contrast with the nobility and the second one about innocence I want to know that before I start reading it, so for example: "Shakespeare shows this by contrasting the lovers' purity with the evil scheming of the other characters. As well as this, his depiction of the lovers' innocence suggests hope for a new world." That's it! Some people struggle with introductions because they say they don't know what they're going to write before they start the essay. It's true that the introduction doesn't need to have everything in it that you're going to write - in fact, it definitely shouldn't. But to write an introduction you do need to have a plan. The best introductions (and essays) are written by people who have taken 5 minutes out of their essay time to work out exactly what they're going to say - it will save you time in the long run and give a clear summary of your argument which will help the marker to give you the marks you deserve.