You should go through your Apache configuration (httpd.conf), PHP configuration (harden PHP in php.ini), install the right modules for both Apache/PHP (Opcache, CloudFlare, etc), if you prefer to use something more modern, you can try switching Apache for a premium option like LiteSpeed to run your webserver. Maybe add Varnish and Memcached, all of these are some of the things you can take a look at in order to optimize your server for speed, performance and security.
Make sure you do take the time to read throughly how each setting affects your server and try to start with some examples that have safe values, work from there to see how your sites perform better. A lot of the times you can't really suggest one configuration for one server since they are all different.
