HELP: My site loads very slow

[boyhermes]

Hi:

I need help. In spite of I installed the quick cache plugin, the site loads too slow.

www.losmejorestutorialesenvideo.com

Usually the main page loads normal, but the problems is when I try to load post and categories. The time response is around 7-9 seconds.

I had to deactivated and erase w3 total cache, because the posts loaded in 15-20 seconds. when I erased the plugin, the time decrease to 6 seconds. Later , the time began to grow. Then I decided to install quick cache plugin. But the site still have problems.

I used compression with gzip, but did not work.
I deactivated all the plugins but the posts loads only a little bit faster, 6-8 seconds.

google speed page says that I have to do the following:

css sprites
defer parsing java scripts
remove redirects chains (gravatar)

I do not know how to do those tasks. please could you help me ?.