There's quite a lot you can do to improve the speed of your website. You can do some research on website performance optimization for WordPress. You will come across terms like minify, gzip compression, image optimizations etc.
A simple way is to use plugins that does these optimizations for you. There are quite a few good ones out there. But be careful not to add too many plugins as this will only increase the loading time.
I suggest JCH Optimize because they do pretty much every optimization needed for your website (less plugins to use), it's really easy to use and they have a free version that you can try. And they support other php cms like Joomla, Drupal and Magento.
W3 Total Cache is also good for caching. and they're are many other plugins you can look into.