How can I speak Old English better?

I LOVE Shakespeare, I read his plays all the time. I like the way Old English sounds, how they use "prithee" and "bly me!" and all that. I would like to learn some substitute words for modern, and grammar too. Grammar really gets me. For Language Arts next semester I may have to write a story or play and I might want to have it in a certain time period and scenario...thank you.