different revision methods will work for different people; make the effort to revise for your mocks so you can see which revision method is best for you.
Is IGCSE and GCSE the same thing? If not, what's the difference.
Similar. They're both the same level qualification, they generally test very similar things (in the same subject of course). iGCSEs are more likely to be taken by international students, or those who go to private schools since they are interationalGCSEs, since (iirc) they don't count for league tables so state schools don't want to disadvantage their league table position by taking them over the very similar GCSEs they can take without them not counting for league tables.
Go to the exam board website you should find alll the past papers and answers there. I used them a great deal when revising for my exams and they are so helpful.