Compression reduces response times by reducing the size of the HTTP response. Gzip is the most popular and effective compression method currently available and generally reduces the response size by about 80%.
<ifmodule mod_deflate.c>AddOutputFilterByType DEFLATE text/text text/html text/plain text/xml text/css application/x-javascript application/javascript</ifmodule>
That's essentially a list of MIME types that gzipping will then apply to. Feel free alter the list to all text based assets you serve.
The HTML5 Boilerplate project offers server configs for all the popular servers. This is it's version for .htaccess
<IfModule mod_filter.c>
AddOutputFilterByType DEFLATE "application/atom+xml" \
"application/javascript" \
"application/json" \
"application/ld+json" \
"application/manifest+json" \
"application/rdf+xml" \
"application/rss+xml" \
"application/schema+json" \
"application/vnd.geo+json" \
"application/vnd.ms-fontobject" \
"application/x-font-ttf" \
"application/x-javascript" \
"application/x-web-app-manifest+json" \
"application/xhtml+xml" \
"application/xml" \
"font/eot" \
"font/opentype" \
"image/bmp" \
"image/svg+xml" \
"image/vnd.microsoft.icon" \
"image/x-icon" \
"text/cache-manifest" \
"text/css" \
"text/html" \
"text/javascript" \
"text/plain" \
"text/vcard" \
"text/vnd.rim.location.xloc" \
"text/vtt" \
"text/x-component" \
"text/x-cross-domain-policy" \
"text/xml"
</IfModule>