You can check with the following points, if it will work for you:
- Check for the query, you are making to fetch the data. Try to rewrite for the better performance.
- Check if you want to use cache functionality so that data retrieval will be faster from cached files.
- You can use minified css and js files instead of normal javascript and css files (there are many third party plugins available which will convert the files to minified one).
- You can use chunk/image sprites instead of using single images for your application.
- Check for any CDN provider (though it will be licensed one, and will cost you) so that files can be stored in other domain instead of your own domain, so that application will be faster.
- Instead of storing all the things in DB, you can try to save in file system so that retrieval will be faster and will not take so much time and will not hit DB frequently.
- Last but not the least, check for ajax/http request which is also responsible for slower down the application.
Hope the above points will help you :)