Seeing that Amazon has priced the usage of EBS as:
$0.10 per GB-month of provisioned storage; $0.10 per 1 million I/O requests
Even though the value is in millions, I/O request add up pretty quickly
... I was wondering if there are any best practices for reducing I/O requests out there.
E.g. Use an instance with more than enough RAM required for your app.. Tweak some OS level parameters.. dont do a 'sync' every couple of minutes :) .... etc.
So the general advice about avoiding premature *micro*optimizations should probably apply here. Think first about making sure you are using the PaaS architecture appropriately, and tweak parameters once you have data. Repost a more specific question (as gareth said).
But I do have one specific optimization, since you asked: add a ramdisk to your linux machines, so that temporary files don't touch storage:
echo "none /tmp/ tmpfs defaults 0 0" >>/etc/fstab
and use vmstat -Sm 5 to watch how much IO is being done.