I teach sonnets and Iambic Pentameter before we start to read any Shakespeare. It helps my students to understand the language. They are able to see that Shakespeare changed the word order to help it fit with the meter, and it helps them to see the purpose in that. I also explain to them that characters of higher social classes speak in iambic pentameter, while the lower class characters do not. It helps with character developement.
It might also be helpful to tell students some of the important phrases we now have thanks to Shakespeare. Doing this allows them to see why we still read him and that it's not as pointless as they may think. Some examples of these are "bated breath," "dead as a doornail, "for goodness sake," and many others. Students usually find this very interesting.