Blog really slow – takes a long time to load

Hi Guys, ever since i started my blog my websites loading speeds have been up and down ranging from 3 seconds to 40 seconds. The website is here – Coolest-tech.com

Whenever i get the blogs loading speed down to something reasonable it slowly creeps back up. I have plugins that apparently increase speed, e.g. W3 Total cache. I also tried WP Minify but that crashed the site for some reason.

Aswell as plugins i also spent a good amount of money on a CDN for my blog called MaxCDN. That again made the blog really quick for a few days. But now its gone back up to anywhere from 20 seconds plus. It needs to be quicker, alot quicker, i dont understand why its so slow.

Please help!

Thanks,
-Michael