The English Faculty does not prescribe one referencing method but its advice is to be consistent, so pick one and stick with it! Your tutor can help advise which method to use. You will find brief MHRA guidelines in the FHS handbook which also includes basic instructions and clear advice.
You can download the MHRA Style Guide or take a look at the few Style Guides held in the Reference section of the Library!
The University has produced a short guide to what constitutes plagiarism, and how to avoid it.
You can also find a useful advice on avoiding plagiarism in this handout created by Turnitin.
RefWorks is an online research management tool that will let you - amongst other things - generate citations and bibliographies.
The Bodleian Libraries has a subscription to RefWorks, so any member of the University can create an account.
If you would like to find out more about this service, you can have a look at the Bodleian Libraries RefWorks webpage.
You might also want to have a look at the Bodleian Libraries' guide to managing your references.