You can create beautiful waves like these on Delta Goodrem's long hair with the use of a curling iron.  First make sure it is a good ceramic one that will make a more even, well conformed curl with less damage.  Using managable sections, working from one side to the other, and from top to bottom, wrap hair around twice, leaving the iron in hair for 5-10 seconds depending on thickness, allowing the bottom of section to hang free.  Remove iron and repeat on same section just below the created wave/curl, continuing until entire section is complete.  Do each section, taking care not to disturb the work.