How to display post type randomly in arguments?

try

'orderby' => 'rand'

Offset: offset (int) – number of post to displace or pass over. Warning: Setting the offset parameter overrides/ignores the paged parameter and breaks pagination. The ‘offset’ parameter is ignored when ‘posts_per_page’=>-1 (show all posts) is used.
source: codex

Nope… It didn’t work.

Oh it worked!! I just forgot to remove ‘order’=>’desc’ Thanks to you.

I am posting an working random-posts-from-from-custom-taxonomy here.. I used it in my old theme and it is 100% functional. just clear the mess… sorry for messy snippet.

<?php

// get the custom post type's taxonomy terms

$custom_taxterms = wp_get_object_terms( $post->ID, 'genre', array('fields' => 'ids') );
// arguments
$args = array(
'post_type' => 'albums',
'post_status' => 'publish',
'posts_per_page' => 13, // you may edit this number
'orderby' => 'rand',
'tax_query' => array(
    array(
        'taxonomy' => 'genre',
        'field' => 'id',
        'terms' => $custom_taxterms
    )
),
'post__not_in' => array ($post->ID),
);
$related_items = new WP_Query( $args );
// loop over query
if ($related_items->have_posts()) :
echo '<div class="widget"><h4 class="related_head">Also Check Out</h4><ul class="related section group">';
while ( $related_items->have_posts() ) : $related_items->the_post();
?>
    <li class="col2 x12"><div class="img"><a href="<?php the_permalink(); ?>"><?php
if ( has_post_thumbnail() ) { // check if the post has a Post Thumbnail assigned to it.
	the_post_thumbnail( 'small_thumb' );
}
else { ?> <img width="60" src="/mp3/albumcover_min.jpg" alt="<?php the_title(); ?> Album thumb image" />
<?php }
?></a></div><div class="related_content"><a href="<?php the_permalink(); ?>" title="<?php the_title_attribute(); ?>"><?php the_title(); ?></a><br/>
<?php echo get_post_meta($post->ID, 'wpcf-total-songs', true); ?> Songs</div></li>
<?php
endwhile;
echo '</ul></div>';
endif;
// Reset Post Data
wp_reset_postdata();
?>

Thank you. It already worked. I want to ask u one more thing. I’ve CPT called product and I’ve one field called slogan. What I want to do is if the field is not empty then show it’s content other wise not to show this field. Can you write a code for this?

if(get_post_meta($post->ID, 'meta-key', true))
    echo '<div class="whatever html u want">'. get_post_meta($post->ID, 'meta-key', true) .'</div>';
}

u can find meta key by inspecting the field in post editor. meta key usually be there as a class/id.

Thanks it worked.