If we're focusing on politics I would argue contemporary knowledge on political events and topics of interest, anything you can link to yourself as well in terms of personal experience or knowledge. Tie in subjects you've taken at A-Level, e.g. Sociology, Politics and Government, English, History, etc and highlight skills related to studying politics. In mine I chose to specify my personal statement a bit further, as I was looking into International Relations or Sociology combined with Politics, so I chose to specialise my statement in diplomacy, and autocracies.
Parts I added included:
- Contemporary knowledge/personal experience
- Work experience/applied skills/supercurricular activities
- extracurricular and school roles (head boy, student council etc (relate to democracy, and democratic process)
- analysis of personal interest/politics, etc
- Subjects and transferable skills, maybe if you didn't take a subject that directly links to politics, try and show how it may have these transferable skills
Hope this helps.