WordPress: Enable Featured Image In A Theme
Most themes already come with this support but if you are building one from scratch and you want to add this ability, just add this add_theme_support code to the functions.php file.
WordPress: Get Featured Image URL
Get the post featured image url with this code.
WordPress: Register a Sidebar (Widget section)
To register a sidebar for the widget area in WordPress, use this code.
WordPress: Get Post Permalink
To get the post permalink in WordPress, use this code.
To get post meta data in WordPress, use this code.