More free homework help on writing introductions is available at the eNotes Topics page.
As with any writing assignment, you first need to make an outline of your paper. Make sure that your outline deals with the prompt you've been given. Then, use your introduction and conclusion to bookend your ideas.
Your introduction should start with a hook (an attention-getter). This could be a quote from the piece, a short story that parallels your ideas, etc. Then, relate your hook to the task at hand: the prompt of your essay. Lastly, briefly state the points you will make in the body of your paper.
Hope this helps. Good luck!
The best thing any professor ever taught me about a good introduction is to use one of 3 things as an attention grabber.
1. a quote
2. a question (that is answered in the conclusion with an opinion)
3. a story that links the reader emotionally or intellectually to the subject.