.htaccess and browser caching for seo

Step1:

Apache's mod_expires module allows settings by file type to control how 
long browsers cache files. This is useful for ensuring browsers cache 
image, Javascript and/or CSS files without making additional unnecessary 
requests when loading pages. 

Step2:

You will need to edit your .htaccess file. Add the following code to the file and

save it.

The timeframe should be one of years, months, weeks, days, hours, minutes or seconds.
Here's an example from one of my sites:

ExpiresActive on
ExpiresByType application/javascript "access plus 1 months"
ExpiresByType image/jpg "access plus 1 month"
ExpiresByType image/jpeg "access plus 1 month"
ExpiresByType image/gif "access plus 1 month"
ExpiresByType image/png "access plus 1 month"
ExpiresByType text/css "access plus 1 months"

Step3: 

Enjoy Folks