Drop all the lightning spells on the most deeply embedded Air Defense.
Use wallbreakers to create a path to the other air defense.
Drop giants and let them destroy the air defense.
Drop all three healers behind the giants.
When defenses around the DE storage have been destroyed deploy the goblins.(Wizard Tower can easily destroy goblins so be careful)
Watch as the goblins steal the DE while the defenses are being distracted by Giants Healer
(No execution notes)
This strategy will get you DE most of the times though might sometimes fail.The main reason I have found for it failing is Giants splitting up. To counter this drop giants in groups and a healer with each group.(7 giants and 1 healer 7 giants and a healer and 6 giants and a healer)