The different template (tpl) files in Drupal

page.tpl.php: controls the layout of the entire page. The overalll screen in which your content types and blocks are laid out

node.tpl.php: used to control the look of each node

block.tpl.php: for control over the look of blocks

page-front.tpl.php: to control the look of just the home page of the site

node-nodetype.tpl.php to affect just one node content type. nodetype names can be found in the type column of the content types list page at administer->content management->content types.... copy node.tpl.php and rename it to node-story.tpl.php for instance and then code away.