A coat hook that strips out of hollow wood door is best fixed with a Molly.
Light duty – plastic anchor
Medium-duty – EZ self-tapping screw, molly
Heavy-duty – sleeve anchor, toggler
To install plastic wall anchors, drill holes slightly smaller than the anchors, and use a screws that are wide and long enough.
The expandable wall anchor, or molly, work very well. Most require a pilot hole, but there is a pointed type available that can be pounded in with a hammer. Mollies work by compressing expanded metal straps that buckle so as the bolt tightens, the umbrella closure pulls tight to the back of the wall.
The toggler is useful because of it’s strength, but also it can be use for any depth of the hollow wall.