I have heard that using grunt/gulp can speed up development by automatically cleaning the static content directories and compiling and generating new css.
How can we configure these and achieve this. Any help is much appreciated!
Thanks
You can check this How to configure a Grunt? to configure grunt.
Follow above link it help to configure grunt.
Don't forget to set your site to developer mode and turn off all caches:
php bin/magento deploy:mode:set developer
php bin/magento cache:disable
Make sure that the mode is not overridden in your webserver config or in your env.php