Related posts are related

gistfile1.aw

<?php

$category_ids = wp_get_object_terms( get_the_ID(), 'category', array( 'fields' => 'ids' ) );
$post_tag_ids = wp_get_object_terms( get_the_ID(), 'post_tag', array( 'fields' => 'ids' ) );

$related_query = new WP_Query( array(
                                    'posts_per_page' => 3,
                                    'post__not_in' => array( get_the_ID() ),
                                    'orderby' => 'rand',
                                    'no_found_rows' => true,
                                    'post_type' => 'post',
                                    'tax_query' => array(
	                                    'relation' => 'OR',
	                                    array(
		                                    'taxonomy' => 'category',
		                                    'field' => 'id',
		                                    'terms' => $category_ids,
		                                    'operator' => 'IN',
	                                    ),
	                                    array(
		                                    'taxonomy' => 'post_tag',
		                                    'field' => 'id',
		                                    'terms' => $post_tag_ids,
		                                    'operator' => 'IN',
	                                    ),
                                    ),
                               ));