Create a custom template file node--type.tpl.php where type is the machine name of your content type.
Place it in your theme's templates folder /sites/all/themes/YOURTHEME/templates and clear/flush the cache to see changes.
Ex: Article content type: node--article.tpl.php
<?php print render($content['field_xxx']); ?>
// custom html goes here
<?php print render($content['field_yyy']); ?>
