Here is a tool from the video:
We see here that your site had a page load time of 3.56 seconds (which is quite good) and is faster then 46% of all their tested websites. This is good, it means you are faster then half the pages out there, but there is still 54% room for improvement
It shows how long every file took to download, thus helps you evaluate what could be slowing it down, etc.
It's biggest recommendation is to "Serve static content from a cookieless domain", it was it's biggest critique. Which would be resolved by the very cheap amazon service I recommended, I imagine.
36% of page load time is due to your images, so to reduce size here would help load times the most. To place an image of your site of the very smallest filesize yet still maintaining quality is the goal, so experimentation with that might be worthwhile.
31% of page load time is due to scripts, which are of course necessary but can always be refined.
It has ways for you to track the speed over time, so you can see the effects of the work you do. I think this is free as well.