What is the recommended method for creating a stable foundation using concrete footing for a 4x4 post?

To create a stable foundation using concrete footing for a 4x4 post, the recommended method is to dig a hole that is at least 12 inches in diameter and 24 inches deep. Place a cardboard tube form in the hole and fill it with concrete, making sure it is level and plumb. Insert a post anchor into the wet concrete and allow it to cure for at least 24 hours before attaching the post. This will provide a strong and stable foundation for the post.