Toiletries and Medical Supplies: I really hope you read this before you leave to come here. There are no stores out here and there is no water. You will be lucky to even have this kind of privacy. I suggest those wet-wipe products. At the very least have some tissue.
Luggage and bags:
Soft bags are better than sturdy suitcases and keep the weight down.
Clothing/Shoes/Weather Gear: Light clothing, if you hike, good shoes or boots something warm for the cold evenings. A waterproof can be a good idea especially for Swakupmund. A hat to keep the sun off your head and naturally sunnies!
Toiletries and Medical Supplies: Sunscreen is very important also is mosquito repellent
Photo Equipment: Bring plenty of film and spare batteries for your camera or flash. You can buy them here but expensive.
Camping/Beach/Outdoor Gear: If you are camping then I'm sure you already know what to bring.
Miscellaneous: A flashlight/ torch is quite a useful item to have with you.
Clothing/Shoes/Weather Gear: The desert is very hot during the day, but it get´s chilly at night, bring warm clothes and of course comfortable shoes.