Undergraduates may well ask you to recommend particular lectures. When you choose the topic for a supervision, it is usually helpful to give students a specific question or statement which can serve as the focal point for an essay. The purpose of the essay is to encourage undergraduates to reflect on what they have read and construct an argument around the question. The Course Organiser will provide sample essay questions in the Paper Guide. You can also take questions from previous exam papers.
Tripos questions are sometimes quite sharply focused, and undergraduates tend to read for the essay.
So if you give students a very sharply focused question, you should strongly encourage them to read more widely around the topic. You should also make sure that your students are aware of the range of different analytical skills, modes of argument and methods of presenting evidence that are needed to cope with different types of question. Here you can usually draw on the Paper Guide though you may wish to supplement this. When you set an essay question, you should also indicate which books and articles they should try to read. First-years in particular may need reassurance that they are not expected to read everything on a long list before writing the essay.