I'm a mixed white-asian student from the UK, thinking of applying to HYPSM this year. I've got back up applications in the UK, so my US applications are just dreams really :)
At AS-Level I got 6As (4As are considered equivalent to a 4.0 GPA) by self-teaching myself a couple of subjects. I also got an A* in an A2 a year early by self-teaching myself another subject. I have a 2200 SAT (760 CR, 760 maths, 680 writing, resitting in decemeber), subject tests in maths L2, physics and english lit pending. I'm ranked somewhere in the top 5 students in my year of 180 i.e. top 2.7% minimum.
I think the biggest strength of my application will be my extra academics. In my own time, I am doing a module from the Open University taken from the third year of their maths degree (it's very unusual for a 17yr old to be doing this kind of work). My first exam is in December, so I'll have some results to put on the application. I am also studying three edX modules (freshman courses from Harvard and MIT). In total, this extra academic workload is rated at 38hrs/week, on top of doing double the average school workload at a top 10 state school.
In terms of extra-curriculars, I'm a keen pianist. In December i'm sitting my Grade 8 piano exam, which is the highest grade in the UK, and this Tuesday I'm sitting the Grade 8 Music Theory exam, which is also the highest national standard. I'm self-taught for both these exams. At school, I'm the elected representative of my house on the school council and an elected House Official. I've arranged and conducted a variety of musical performances at school including a choir, jazz band and one-act musical, and I enjoy public speaking and debating.
I'm a regular volunteer at a dementia care home (>100hrs) and I've written a research paper about a new means of diagnosing dementia and lead a team to complete a nationally published research paper on stem cells. I've planned and completed a Gold Duke of Edinburgh's expedition. I also have a 10hr/week job, which I use to fund my university maths module.
As an international student, I don't know much about HYPSM admissions, so any chances would be much appreciated :)