Ideally you should be studying for a degree with significant mathematical content; statistics, maths, engineering, science and economics are all ideal subjects. The advice that I was given as a student, and that I still give whenever speaking to students today, is to study a subject that you enjoy. You are better with a good class of degree than a poor degree and some exemptions, and you are more likely to do well at something you enjoy.
Tenacity is essential, as the actuarial exams are demanding. To be accepted as an actuarial student usually demonstrates that you have the ability to qualify. The two reasons for not qualifying are that a) the student ‘learns well how to fail’ and gives up, or b) gives up, albeit for some wholly justifiable reasons (such people are often referred to as ‘unqualified successes’).
In theory, exemptions make it easier to qualify, but you need practical experience in an office in order to integrate the theoretical knowledge and to learn the jargon. Take advantage of the long summer holidays before you graduate to gain as broad a range of experience as possible.
Actuaries need good communication skills. It used to be said that you know you are talking to an extrovert actuary because they look at your shoes rather than their own when they speak. This is no longer true. As an actuary you will often need to explain complex technical information to non-technical audiences.