just use the order attribute (which btw is also available in quick edit).

if you cannot see it in individual posts/menu items, you might have to click on “screen options” and check “attributes” first

there are also a variety of drag and drop (custom) post type plugins available on wordpress if you prefer to sort the order that way

alternatively – as of version 2.11.8.14 – you can sort items by id, title or date , overriding the default sort order (wppizza->layout => Menu items sort order (in category):)