Just add this to your theme's functions.php file:
add_action('admin_head', 'wptechs_admin_cleanup');
function wptechs_admin_cleanup() {
echo '<style>
#wp-admin-bar-wp-logo {display: none !important;}
#wp-admin-bar-comments {display: none !important;}
#wp-admin-bar-imagify {display: none !important;}
#wp-admin-bar-wpseo-menu {display: none !important;}
#wpfooter {display: none !important;}
#dashboard_primary {display: none !important;}
#dashboard_quick_press {display: none !important;}
#jetpack_summary_widget {display: none !important;}
}
</style>';
}