Starboard side (right). Most of the time (more than 9 / 10 times on my personal count), ship approaches north and parallel of DXB heading south east. Then, 10 miles off DXB, it makes a U-turn. At landing, Dubai is on the left, but you are too much inland so that you won't see much. It's better to see the landscape on approach, while still over 4000 feet.

For take off, sit on the port side (left), as ship faces the sea. Weather permits, you'll be able to see Burj Khalifa, the World, and Palm Jumeirah. If your flight is heading southwest (which is not the case for YTZ), you'll fly shortly along Dubai coast.