Aside from the obvious ones such as numeracy and interpersonal skills, key skills will include determination and self discipline (to get through the difficult professional examinations) and an interest in the business world generally. An ability to work in (and ultimately lead) teams, strong analytical skills, good verbal and written communication skills and curiosity (particularly on the audit side) are some of the others you could mention - if you aren't strong in some of these areas then you may have problems making a persuasive case for yourself.

You are likely to be asked many questions seeking evidence of these particular competencies and will be expected to give examples which are backed up with evidence: for example, if asked about your leadership qualities, you should give an example of where you led a group successfully rather than just stating 'people always look to me to take the lead'.