Default WP .htacess code
# BEGIN WordPress
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
# END WordPress
expires headers
<FilesMatch "(?i)^.*\.(ico|flv|jpg|jpeg|png|gif|js|css|woff)$"> ExpiresActive On ExpiresDefault A2592000 </FilesMatch>
If we need to set a separate Expire Headers rule for each of your filetypes we can use this snippet
ExpiresByType image/png A2592000 ExpiresByType image/gif A2592000 ExpiresByType image/jpg A2592000 ExpiresByType image/jpeg A2592000 ExpiresByType text/javascript A2592000 ExpiresByType application/x-javascript A2592000 ExpiresByType text/css A2592000