wordpress-plugin.php

<?php
/*
Plugin Name: My Plugin
Plugin URI:	http://URI_Of_Page_Describing_Plugin_and_Updates
Description: This describes my plugin in a short sentence
Version:		 1.0.0
Author:			Webikon (John Doe)
Author URI: http://URI_Of_The_Plugin_Author
License:		 GPL2
License URI: https://www.gnu.org/licenses/gpl-2.0.html
Domain Path: /languages
Text Domain: my-plugin
*/

/**
 * Main MyPlugin Class.
 *
 * @class MyPlugin
 * @version	1.0.0
 */
class MyPlugin {

	/**
	 * The single instance of the class.
	 *
	 * @var MyPlugin
	 * @since 1.0.0
	 */
	protected static $_instance = null;

	/**
	 * Custom Property.
	 *
	 * @var $custom_property
	 */
	public $custom_property = null;	

	/**
	 * Main MyPlugin Instance.
	 *
	 * Ensures only one instance of MyPlugin is loaded or can be loaded.
	 *
	 * @since 1.0.0
	 * @static
	 * @see MyPlugin()
	 * @return MyPlugin - Main instance.
	 */
	public static function instance() {
		if ( is_null( self::$_instance ) ) {
			self::$_instance = new self();
		}
		return self::$_instance;
	}	

	/**
	 * Custom Method.
	 * @return custom_method()
	 */
	public function custom_method() {
		return 'Custom Method';
	}	

}

/**

 * Main instance of MyPlugin.
 *
 * Returns the main instance of MyPlugin to prevent the need to use globals.
 *
 * @since	1.0.0
 * @return MyPlugin
 */
function MyPlugin() {
	return MyPlugin::instance();
}

//Now we can easily access any available properties and methods of MyPlugin object

MyPlugin()->custom_property;

MyPlugin()->custom_method();