Please do not attempt to do the following tasks if you are not sure what you are doing.
1. Image Optimization
Install the EWWW Image Optimizer plugin (http://wordpress.org/plugins/ewww-image-optimizer/). We do not recommend manual image optimization unless you are already comfortable doing that.
2. CDN - We recommend a reverse-proxy based solution, such as CloudFlare, due to its easy set up.
3. Enable gzip compression for static files. How exactly you do this will depend on your hosting configuration - ask your hosting provider if you are not sure.
4. Consider switching to HTTP/2. You will need an SSL certificate for this. If you use CloudFlare - choose "Full SSL" after configuring SSL on your server. Ask you hosting provider for help with the server configuration. (You can get a free certificate from Let's Encrypt, if you hosting provider supports this option)
5. If you have switched to HTTP/2, do not combine CSS/JS files. This will negatively affect performance for HTTP/2 sites.
6. Consider using this plugin - https://wordpress.org/plugins/scripts-to-footerphp/ (we use it on our demo sites). Refer to the plugin's FAQ (found on the same page) if you have any issues.
7. Unless you need the advanced W3 Total Cache features, install and activate WP Super Cache (https://wordpress.org/plugins/wp-super-cache/). Enable caching in Settings/WP Super Cache. We no longer recommend W3 Total Cache for all sites.
8. Enable lazy loading for all LayerSlider/Slider Revolution sliders. Consider limiting the number of sliders (and slides) on you home page.
9. In general, consider limiting the content on your home page. Multiple sliders, form (especially when using "form builder" plugins such as Ninja Forms) will slow your page down.
10. If you use Jetpack, disable the modules that you don't need. Also disable WP Core features which you don't use, such Emoji (use https://wordpress.org/plugins/disable-emojis/)
Regardless of any optimizations, if you have lots of stuff on your site, it will be slower than a simple text-only page. Your goal is to strike a balance between performance and content which works for you. The recommendations above are just a list of good practices, but they are not a universal solution for all performance-related issues.
Also, our recommendations are not the only "true" solution. You can find an alternative approach described here: http://www.sparringmind.com/speed-up-wordpress/