This is very simple to write our own plug-in. Following is the syntax to create a method:
The guideline recommended by the jQuery team is as follows:

• Any methods or functions you attach must have a semicolon (;) at the end.
• You should use this.each to iterate over the current set of matched elements - it produces clean and compatible code that way.
• Your method must return the jQuery object, unless explicity noted otherwise.
• Prefix the filename with jquery, follow that with the name of the plugin and conclude with .js.
• Always attach the plugin to jQuery directly instead of $, so users can use a custom alias via noConflict() method.

Structure of Plugin

//You need an anonymous function to wrap around your function to avoid conflict  
(function($){  
  
    //Attach this new method to jQuery  
    $.fn.extend({   
          
        //This is where you write your plugin's name  
        pluginname: function() {  
  
            //Iterate over the current set of matched elements  
            return this.each(function() {  
              
                //code to be inserted here  
              
            });  
        }  
    });  
      
//pass jQuery to the function,   
//So that we will able to use any valid Javascript variable name   
//to replace "$" SIGN. But, we'll stick to $ (I like dollar sign: ) )         
})(jQuery);  

Plugin with options

(function($){  
  
    $.fn.extend({   
          
        //pass the options variable to the function  
        pluginname: function(options) {  
  
  
            //Set the default values, use comma to separate the settings, example:  
            var defaults = {  
                padding: 20,  
                mouseOverColor : '#000000',  
                mouseOutColor : '#ffffff'  
            }  
                  
            var options =  $.extend(defaults, options);  
  
            return this.each(function() {  
                var o = options;  
                  
                //code to be inserted here  
                //you can access the value like this  
                alert(o.padding);  
              
            });  
        }  
    });  
      
})(jQuery);