advice for studying politics

I got my predicted grade which is AAA this means I can't apply to study law at the unis I want to (UCL, KCL, LSE) but I can apply to study politics or politics and international relations. I somewhat keep up with the news but not as much as a politics student would. I generally just look out for commercial news. Can someone please give me advice for my personal statement on politics? Also, some reliable sites where I can read how the political system in the UK works. And lastly any book recommendations. Please someone help me.