Best way to include jQuery and fire with script at bottom of container

You typically should use the jQuery version that’s built in. There are instances where you might want to use wp_dequeue_script(‘jquery’) and then add a different version of jQuery.

Here’s the best way to add a script dependent on jQuery:

function theme_register_scripts(){
   wp_enqueue_script('jquery');
   wp_enqueue_script('myscript-name', get_bloginfo('stylesheet_directory') . '/js/myscript.js', array('jquery'));
}
add_action('wp_print_scripts', 'theme_register_scripts');

The third argument of wp_enqueue_script is the script dependency which we identify as jQuery. This guarantees that jQuery will be printed before your custom script is printed.