One of the best tools, it would give you suggestions to improve page speed as well..

GTmetrix | Website Speed and Performance Optimization

I like to use Web Page Test WebPagetest Test Result - Dulles : www.warriorforum.com/ - 06/11/13 20:07:39

They give you hints and tips on optimizing your site load time.

Frontend Performance Optimizing is something you can not solve with just using a CDN.

You need to check your code, CSS, JS, images and everything that produces http-requests.

Especially 3rd party scripts can be a pain in the a**...

I am doing Frontend Performance Optimizing since 2009, optimizing loading time begins with the webserver and ends with tons of testing.

You need good knowledge of what you are doing... and yes, I know what to do.

Every website that I do is optimized for loading speed.

Best practices for speeding up your web site from Yahoo Developer Network. At this link you can find all the techniques for improving your site performance.

You can test your site loading speeds in the pingdom website speed test (it's free)

You get to see all the images sizes, scripts and literally everything that is taking a while to load so you can fine tweak every single component on your site.

If you're running Wordpress sites, I suggest WordPress Hosting by Synthesis. We just moved three of our sites over there and the speed is fantastic.

3rd party integrations are indeed the biggest pain.. I've optimized my fairly graphical site to under 1sec loading time (which took quite a bit of effort) however some plugins and tracking stuff just slow it down with 2 - 4 seconds.. you can try some caching where possible but this is usually pretty limited.

Especially Facebook API is slow as f-ck