Properly render a field

Drupal offers a few (sometimes complicated...) solutions to output a field. Lets take an example with a date field.
To display the full rendered field: field_view_field()

$mydate = field_view_field('node', $node, 'field_mydate');
print render($mydate);
 
/*display
<div class="field field-name-field-mydate field-type-date field-label-above">
  <div class="field-label">Date:</div>
  <div class="field-items">
    <div class="field-item even">
      <span class="date-display-single">Wednesday, 10 October, 2012</span>
    </div>
  </div>
</div>
*/

note: default wrappers will be displayed (even if you choose to not display the label in the display settings for instance...)
to choose a different formatter than the default one

$mydate = field_view_field('node', $node, 'field_mydate', array('type'=>'my_custom_one');

To display the raw value of the field: field_get_items()

$mydate = field_get_items('node', $node, 'field_mydate');
print $mydate[0]['value'];
//display 2012-10-10T00:00:00

will display the value as it exists on the db. Can be useful for strings.

To display the formatted value, without any < div >: field_view_value()

$mydate = field_get_items('node', $node, 'field_mydate');
$output = field_view_value('node', $node, 'field_mydate' , $mydate[0]);
print $output['#markup']; //for files use render($output);
//display <span class="date-display-single">Wednesday, 10 October, 2012</span>

will display the formatted value, with only a surrounding span.
note: you can specify a formatter to display an image with a preset

$output = field_view_value('node', $node, 'field_myimage', $myimage[0], array(
  'type' => 'image',
  'settings' => array(
    'image_style' => 'thumbnail',
    'image_link' => 'content',
  ),
));

not so easy !!

Display errors - WSOD

The bootstrap override the values you could set to display error ad the reporting level. To be 100% sure everything is printed out when something fails in a blank screen (wsod), make index.php like this:

Drupal offers a few (sometimes complicated...) solutions to output a field. Lets take an example with a date field.
To display the full rendered field: field_view_field()