This is what I used, partially from http://codex.ww.wp.xz.cn/Template_Tags/query_posts. For mine I needed to include a specific tag and exclude another tag.
<?php
$args=array(
'showposts'=>10,
'offset'=>11,
'tag__in' => array('21'),
'tag__not_in' => array('20'),
);
query_posts($args);
while (have_posts()) : the_post(); ?>
STUFF
<?php endwhile; ?>
