For those looking for tips, I would suggest that by far the most important thing for any applicant is to consider what attributes a BA pilot would need as part of their role (e.g. the pilot competencies), and then ensure that you pursue a variety of life experiences which allow you to develop and demonstrate those attributes. They are also looking for demonstrable passion for aviation, so they can be sure of your commitment to the career. As others have noted, once you begin passing through the various stages, they explain what is required at each stage. For example, this year there was a slidepack which gave examples of the types of questions asked for maths/detail checking etc. You can then search the internet and this forum for how to prepare and practice.