To be a competitive applicant and to be successful at Oxford or Cambridge, students must articulate why they want to study their chosen course. Passion for one's chosen course, high grades in relevant subjects, and sometimes aptitude testing are the most important factors. To browse courses, check the Oxford and Cambridge websites.
Reading, studying, and/or researching around the subject(s) that goes beyond the IB syllabus will demonstrate who you are as a thinker in this academic area. Cambridge has released an excellent website called HE Plus, and has a list of suggested readings, which can be a starting point for exploration in many different areas of study. Oxford provides a list of Suggested Subject Resources to give you an idea of the kind of material you might engage with during your course. If you are interested in one of these two selective universities, it is never too early to pursue super-curriculars.
In addition to reading around the subject, "supercurriculars" could also mean participating in academic societies, independent research, taking an online course, internships/job shadowing, taster lectures, or speaking with professionals.
Some courses at Oxford and Cambridge have admission testing as an extra element of the application. Check individual courses to see what the testing requirements are, as you will likely need to prepare over the summer between Grade 11 and 12. Testing registration opens around late August and closes around mid-September in Grade 12. Students will take the exams between October and November in Grade 12.
Both Oxford and Cambridge also conduct interviews; they normally take place in November of Grade 12. The interviews are subject-specific and we will offer some practice interviews in term one of Grade 12 if you would like to do this.
When you apply to Oxford or Cambridge, you will choose a "college" to live and study within. You can also choose to submit an "Open" application and the university will assign you to a College. Whichever college you study in, your degree will come from the university so it does not affect your academic experience. You can look at the university websites to get an idea of the colleges, their facilities, and locations.