Tried and trusted plugin boilerplate for jQuery

jquery_boilerplate.js

// http://stefangabos.ro/jquery/jquery-plugin-boilerplate-revisited/
(function($) {

    $.pluginName = function(element, options) {

        var defaults = {
            foo: 'bar',
            onFoo: function() {}
        };

        var plugin = this;

        plugin.settings = {};

        var $element = $(element);

        plugin.init = function() {
            plugin.settings = $.extend({}, defaults, options);
            // code goes here
        };

        plugin.foo_public_method = function() {
            // code goes here
        };

        var foo_private_method = function() {
            // code goes here
        };

        plugin.init();

    };

    $.fn.pluginName = function(options) {

        return this.each(function() {
            if(undefined === $(this).data('pluginName')) {
                var plugin = new $.pluginName(this, options);
                $(this).data('pluginName', plugin);
            }
        });

    };

})(jQuery);