To hang Christmas ornaments on a tree, start by choosing a variety of ornaments in different shapes and sizes. Hang the ornaments towards the top of the tree first, then gradually work your way down, placing the larger ornaments lower on the tree. Place the ornaments in a way that creates a balanced and aesthetically pleasing design. Use different types of hooks and hangers depending on the type of ornament you're using. Finally, make sure to evenly distribute the ornaments on all sides of the tree for a balanced look.