I scored 98% in the exam and the best revision for me was just watching the news. Politics and world news can be boring however, It really helped me with the exam and discussing with people to get a different perspective.
i am also doing citizenship GCSE this year, i find it helpful to do
make revision quizzes, and get someone to test you
make mind maps
do a lot of past papers
watch or read the news
teach others what you have learnt, that way it can stay in your head
and take breaks, you wont be able to concentrate for a long time