How to theme the $item in views-view-grid.tpl.php I'm just beginning to learn theming Drupal 7, and have encountered something I can't seem to find any info on (and my experiments have no effect).

In tao/rubik theme, and in many others there is the  views-view-grid.tpl.php template which arranges the resulting items from a view in a grid design.

Now, at the very end, after splitting into rows and columns there is a print $item which is the section that prints the actual node content/teaser in the grid square. I'm assuming the content is a node, since this is what I set the view block to display, also I set it to display the full content of that single node.

However, no matter what I do, I can't seem to modify the template of this node... how should the template be called? should it be placed somewhere special? 

What am I missing?
If you are asking how to theme the display of a node, those templates have names like node.tpl.php, node--NID.tpl.php, node--TYPE.tpl.php, etc.  Lots of information on templates can be found here