There are quite a few ways on how to optimize your site. Here are a few steps you can take to increase your sites performance (most of them have plugins:
Cache your site: use cache tools like WP Super Cache. Cache will ensure your site will be held in memory as a static page, this means your server doesn’t have to re-process everything.
Enable server side compression: If you have a good hosting, you can go a bit more technical and optimize your server settings to help you with performance.
All these tools are freely available, and are, with some time invested pretty easy to handle.