Show Tag-Specific or Category-Specific Posts

Hey all, starting a new thread since I figured out my other issue.

I’ve been Googling around but I’m pretty new to php and WordPress so I’m not sure why nothing I’ve tried is working, but I’m trying to get my feed to only show posts either by tag or by category.

Here’s my code so far:

<?php query_posts('post_type=post&post_status=publish&posts_per_page=10&paged='. get_query_var('paged')); ?>

 <?php if( have_posts() ): ?>
 <?php while( have_posts() ): the_post(); ?>

   <div id="post-<?php get_the_ID(); ?>" <?php post_class(); ?>>

   <h2 class="entry-title"><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h2>

   et cetera....

Any ideas? Thanks for the help!