Hello,
I am Magento and Aws expert with 7+ yrs of extensive experience.
I have already worked on this kind of projects.
I have a plan ready to give you result.
1) Install nginx , optimize nginx according to your server configuration..
2) Redis for key object storage and session storage , as magento's session storage is in file and consumes lot of memory and takes time.
3) APC or memcache.
4) FPC must.
5) will optimize MySQL too as per I/O requests.
5) microcache or varnish cache for fast response processing.
please let me know if above looks good , I am eager to work on this.
trust me , I won't disappoint you.
Thanks,
Suyog