Proper linking in WordPress theme templates

wp_links_includes.php

<?php
/**
 * URLs
 */
echo home_url( 'contact' );
echo network_home_url( 'contact' );

/**
 * Static theme files
 */
?>
<img src="<?php echo get_template_directory_uri(); ?>/images/example.jpg" alt="Example"?>
 
<?php
/**
 * Scripts and styles
 */
wp_enqueue_style(
	'prefix-css-example',
	get_template_directory_uri() . '/css/example.css',
	array(),
	NULL
);
if ( is_front_page() ) :
	wp_enqueue_style(
		'prefix-css-example',
		get_template_directory_uri() . '/css/example.css',
		array(),
		NULL
	);
endif;

/**
 * Loading templates
 */ 
get_template_part( 'path/slug', 'name' );
/**
 * Passing variables to the template - require() does not make the scope available
 * but it extracts all the WP_Query vars, so we can cheat a bit
 */
set_query_var( 'my_var', $my_var );
get_template_part( 'path/slug', 'name' );