I've not read it, but I can offer some general advice.
- Relax. If you stay calm about the whole thing, you'll do better than if you get yourself worked up about the exam.
- Sleep. Make sure you get plenty of sleep beforehand, you'll want to be firing on all cylinders.
- Observation. Make sure you understand the question and what it is asking you to do.
- Quotation. If you are required to use quotations from the text to answer the question, use a few quotes and get a lot of analysis out of each one rather than a lot of half-arsed ones.
Oh, and make sure you give the sonnet another quick read through before you go in to the exam.
Good luck man, hope it all turns out well.