Drupal 7 Panels Custom Layout: How To Create

Here are the tips.

1. Add to the .INFO file plugins[panels][layouts] = panels-layouts

2. Create panels-layouts folder in the YOURTHEME folder

3. Create new yourlayoutfolder in the panels-layouts 

3.1. add to it file yourlayout.tpl.php with

<?php print $content['header'];?>
<?php print $content['left'];?>
<?php print $content['right'];?>
<?php print $content['footer'];?>

3.2.  add to it file yourlayout.inc file with

<?php

/**
 * implementation of hook_panels_layouts()
 */
// Plugin definition
$plugin = array(
  'title' => t('yourlayout'),
  'category' => t('Columns: 1'),
  'icon' => 'icon.png',
  'theme' => 'yourlayout',
  'regions' => array(
  'header' => t('header'),
  'left' => t('=left'),
  'right' => t('right'),
  'footer' => t('footer')
  ),
);