I'm struggling to understand the language Shakespeare uses. How can I improve my understanding?

One thing I'd recommend is getting a copy of the play you're studying with a translation into modern English, or an accompanying book of notes such as York Notes or Cliff Notes. These will clearly explain what is happening in each scene. You can even access the website 'No Fear Shakespeare' which has online copies of Shakespeare plays with translations into modern English: http://nfs.sparknotes.comAlso, the more you reread a text and study it's context (in class as well as at home), the more familiar you'll become with Shakespearian language.