How can I make up for bad GCSE results?

Hello, I'm pretty disappointed with my gcse results. I got 3A*s, 6As and 1B. I really wanted to go to LSE for economics but I know they look at gcse results really harshly. Is there anything I can do to help me become a strong candidate (besides working my arse off and getting As at AS-Level? I'm taking maths, physics, economics and biology).

I've just signed up for the Gold Duke of Edinburgh award with my school and I've put down to do a MOOC (Massive Open Online Course) during my enrichment time and it would be on something economical. Do you think this would be worth it? Is there anything else I can do that I could put in my personal statement when applying that would hopefully make them overlook my bad grades?
Thanks, anna x