Magento: Merge Javascript and css files

To spped Up Your Site You needd to follw these Steps:

1) Go to admin section
2) Go to System->Configuration->ADVANCED (Developer)
3) Set “Merge JavaScript Files” to Yes (“No” is default)
4) What left is to Flush Javascript/CSS Cache at Cache management admin interface.

After That take a look at the source file of your page:

BEFORE:

AFTER:

Note: You Can Do the same thing for css