The books on Shakespeare are located on the main floor in the PR (British Literature) section - PR 2753-PR3112. Sometimes just browsing around can help you figure out what approaches scholars have taken to Shakespeare's works. Skim tables of contents to see what's inside. Remind yourself it's time well spent because it will give you ideas. Chill. Sit on the floor if you want. Go in pairs and make noise. We don't mind.
Helpful clue: newer books have the year of publication as the last part of the call number. That might help you focus on the not-too-crusty old stuff.
Some things to know about the catalog: you can limit by year of publication, to print books, and (if you're greedy) search libraries worldwide and request books from other libraries. It takes a few days, but it's free.
These days he would be so busted. Luckily, there was no copyright law when Shakespeare was ripping off, er, being inspired by others. Curious where he got his ideas? It's all here.
It's a busy time of year (when is it not?) and you may feel stressed. Shoot me an email if you can't find something, something seems broken, or you need a shoulder to cry on because you're feeling tempest-tossed. We can communicate over email (fister @ gustavus.edu) or meet in person, as you like it. The other librarians are happy to help, too, but I may be Shakespeare's biggest fan in the library, so I'm interested in what you're working on.