A tip concerning the new @wordpress/block package: it supports hot reloading! With it, whenever making a change in the block's javascript file, the page is automatically refreshed, which greatly speeds up development.

It doesn't mention how to enable it in the package's documentation, so here it goes: Add a script with src http://localhost:35729/livereload.js, like this:

if (defined('ENABLE_HOT_RELOADING_FOR_DEV') && ENABLE_HOT_RELOADING_FOR_DEV) {
wp_register_script('livereload', 'http://localhost:35729/livereload.js');
wp_enqueue_script('livereload');
}

And add define('ENABLE_HOT_RELOADING_FOR_DEV', true); to wp-config.php