wp-query-abstraction.php

<?php

// Hook into WordPress before the query runs
add_action( 'pre_get_posts', 'pj_sort_it_better' );

// Modifies the WP_Query object
function pj_sort_it_better( $query ) {
	
	if ( is_page( 'The Page Name' ) ) {
		
		$query->set( 'meta_key', 'pj-rating' );
		$query->set( 'order', 'DESC' );
		$query->set( 'orderby', 'meta_value' ); // or meta_value_num for numbers
		
	}
	
}