How do I white label my self-hosted site created by wordpress?

I have seen code in an answer to this question, how to remove the promotional back link to WordPress.org in my theme. I have added this to my theme’s CSS but there is no change.

Am I missing see some thing? Apologies for my Ignorance .

Code I have used:

#site-generator {
display: none; }

How can you remove the widgets from dashboard and add new customized widgets ?
Is there possibility to hide the date and time from posts ?

Update :Could anybody tell me ,If I can remove the term ‘wordpress’ from displaying on title bar?

Here is the code I always use whenever I setup a new wordpress blog:

CUSTOM ADMIN FOOTER TEXT

// CUSTOMIZE ADMIN FOOTER TEXT
   function custom_admin_footer() {
    echo '<a href="http://www.netconstructor.com/">Website Design by NetConstructor, Inc.</a>';
   }
   add_filter('admin_footer_text', 'custom_admin_footer');

REMOVE VERSION INFO FROM THE HEAD OF FEEDS

// REMOVE VERSION INFO FROM THE HEAD OF FEEDS
   function complete_version_removal() { return ''; }
   add_filter('the_generator', 'complete_version_removal');

REMOVE JUNK FROM THE HEADER OF PUBLIC WEBSITE PAGES

// REMOVE JUNK FROM THE HEADER OF PUBLIC WEBSITE PAGES
   remove_action('wp_head', 'rsd_link');
   remove_action('wp_head', 'wp_generator');
   remove_action('wp_head', 'feed_links', 2);
   remove_action('wp_head', 'index_rel_link');
   remove_action('wp_head', 'wlwmanifest_link');
   remove_action('wp_head', 'feed_links_extra', 3);
   remove_action('wp_head', 'start_post_rel_link', 10, 0);
   remove_action('wp_head', 'parent_post_rel_link', 10, 0);
   remove_action('wp_head', 'adjacent_posts_rel_link', 10, 0);

REMOVE THE WORDPRESS UPDATE NOTIFICATION FOR ALL USERS EXCEPT SYSADMIN

// REMOVE THE WORDPRESS UPDATE NOTIFICATION FOR ALL USERS EXCEPT SYSADMIN
   global $user_login;
   get_currentuserinfo();
   if ($user_login !== "sysadmin") {
    add_action( 'init', create_function( '$a', "remove_action( 'init', 'wp_version_check' );" ), 2 );
    add_filter( 'pre_option_update_core', create_function( '$a', "return null;" ) );
   }

CUSTOM ADMIN LOGOS:

// CUSTOM ADMIN LOGIN HEADER LOGO
   function my_custom_login_logo() {
    echo '<style type="text/css"> h1 a { background-image:url('.get_bloginfo('template_directory').'/images/excitesteps-login-logo.png) !important; } </style>';
   }
   add_action('login_head', 'my_custom_login_logo');



// CUSTOM ADMIN LOGIC HEADER LOGO
   add_action('admin_head', 'my_custom_logo');
   function my_custom_logo() {
    echo '<style type="text/css">#header-logo { background-image: url('.get_bloginfo('template_directory').'/images/excitesteps-icon.gif) !important; }</style>';
   }



// CUSTOM ADMIN LOGIN HEADER LINK & ALT TEXT
   function change_wp_login_url() {
    echo bloginfo('url');
   }
   function change_wp_login_title() {
    echo get_option('blogname');
   }
   add_filter('login_headerurl', 'change_wp_login_url');
   add_filter('login_headertitle', 'change_wp_login_title');