Find:

<?php comments_template(); ?>

And replace with:

<?php if('closed' != $post->comment_status) comments_template(); ?>

That’s it – «Comments are closed» is history.

I will show you two options; displaying related Posts based on either Tags or Categories. Put the code in your single.php where you want to display related Posts. Right above <?php comments_template(); ?> is probably the best place.

The following will display the five most recent Posts which share the same first Tag of the Post:

<?php
$tags = wp_get_post_tags($post->ID);
if ($tags) {
	$first_tag = $tags[0]->name;
	$args = array(
		'numberposts' => 5,
		'tag' => $first_tag,
		'exclude' => $post->ID
	);
	$related = get_posts($args);
	if($related) {
		echo <div id="relatedposts">';
		echo <h4>Related Posts</h4>';
	  	echo<ul>';
		  foreach ( $related as $rel ):
			echo <li><a href="'. get_permalink($rel->ID) .'" rel="bookmark" title="Permanent Link to '. $rel->post_title .'">'. $rel->post_title .</a></li>';
		  endforeach;
	    echo </ul>';
	    echo </div>';
 	 }
}
?>

If you don’t use Tags, or simply just want to find related Posts based on Category, the following code will do that – displaying the five most recent Posts from the first Category of the Post.

<?php
$cats = get_the_category();
if ($cats) {
	$first_cat = $cats[0]->cat_ID;
	$args = array(
		'numberposts' => 5,
		'category' => $first_cat,
		'exclude' => $post->ID,
	);
	$related = get_posts($args);
	if($related) {
		echo '<div id="relatedposts">';
		echo '<h4>Related Posts</h4>';
	  	echo'<ul>';
		  foreach ( $related as $rel ):
			echo '<li><a href="'. get_permalink($rel->ID) .'" rel="bookmark" title="Permanent Link to '. $rel->post_title .'">'. $rel->post_title .'</a></li>';
		  endforeach;
	    echo '</ul>';
	    echo '</div>';
 	 }
}
?>

The upshot of using this method, as opposed to a plugin, is that you have complete control and can display and style the related Posts as you see fit.

In the category.php of your Theme (if you don’t have a category.php you can duplicate index.php and rename it), add this line above the Loop (which usually starts with <?php if (have_posts()) : ?>):

<?php query_posts('orderby=title&amp;order=ASC'); ?>

You can extend this by adding links for which sort type you want. In your category.php add this where you want the links to appear:

<p>
 Sort by:
 <a href="<?php echo str_replace(('?'.$_SERVER['QUERY_STRING']), '', $_SERVER['REQUEST_URI']); ?>">Date</a>
 | <a href="<?php echo str_replace(('?'.$_SERVER['QUERY_STRING']), '', $_SERVER['REQUEST_URI']).'/?sort=title'; ?>">Title</a>
 </p>

This will display like this: Sort by: Date | Title

Then use this code above the Loop:

<?php if($_GET['sort'] == 'title') query_posts('orderby=title&order=ASC'); ?>

But there are ways around this. The plugin Custom Query String Reloaded lets you set a different numbers of Posts for everthing from the frontpage, to archives and categories.

You don’t need to use a plugin, however, if you know your way around your Theme-files. To change the number of displayed Posts, you simply need this little code snippet:

<?php query_posts('posts_per_page=5'); ?>

Insert it above the Loop in your template-files, and change the number to the number of Posts you want to display. Remember to use Conditional Tags if you want different results on different pages. For example, if you want to show five Posts on the frontpage only, you add this code above the Loop in your index.php:

<?php if(is_home()) query_posts('posts_per_page=5'); ?>

The Loop (usually) starts with the line <?php if (have_posts()) : ?>, so insert your code above this.

This can be used in practically every template-file that deals with multiple Posts; index.php, archives.php, category.php, and so forth.