Eliminate render-blocking resources There are a number of WordPress plugins that can help you inline critical assets or defer less important resources. Beware that optimizations provided by these plugins may break features of your theme or plugins, so you will likely need to make code changes.
Serve images in next-gen formats Consider using the Performance Lab plugin to automatically convert your uploaded JPEG images into WebP, wherever supported.
Defer offscreen images Install a lazy-load WordPress plugin that provides the ability to defer any offscreen images, or switch to a theme that provides that functionality. Also, consider using the AMP plugin