First off, it looks like you’re loading a single image for your page background and scaling it up inside your HTML. Try using the CSS ‘background’ attribute to do this instead.
The fastest and simplest way to improve performance is to install and configure a caching plugin like W3 Total Cache. This will compress your site and reduce the amount of processing PHP has to do by creating static files for the server to use.
Your site also calls a huge number of external assets like JavaScript files. Minifying these using W3 Total Cache can greatly reduce your load times, by putting these all into a single file. You may also want to look at what assets are being loaded, and whether you need all of them.