What is needed for admission to KCL?

I am currently in year 11 and am thinking about applying to KCL. It seems like the perfect university with it being in the centre of London.
I was wondering if anyone could help me know what it is I should think about getting involved in before applying, is there anything that they like to see?
Also I was wondering how much of a role GCSE's play, I am predicted all A's and A*'s with a couple of B's.
If anyone has gotten into KCL, it would be extremely helpful in hearing how their application process went and how the entire thing works based on the credentials they had.

hey! my GCSE grades were pretty average (mostly Bs and Cs) because i wasn't really into education at that point in my life. even my first year AS grades weren't very good, but i managed to work my way up with an AAA offer for king's. obviously the course you're hoping to take has an impact, but for me my previous academic achievements obviously weren't a massive issue. i think uni's are also very interested in people who express enthusiasm/interest in the subject they're applying for. but, again, it depends on your course - some have particular GCSE requirements, usually for maths and english.