First of all get up early. Not only the light is the best, but also the temperature is still all right. During mid-day you only want to be at the pool or sit still in the shade or well, have a nap.
Bring a macro lens, if you have. The desert offer the opportunity to photograph interesting small animals, grass, flowers, stones and as in Namibia ancient rock drawings.
Use the dramatic dimensions of the desert to put animals like a gemsbok in perspective, walking into the depth of the image.
Do, if possible a hot air balloon ride. This will offer you beautiful views on the incredible landscape of the desert. Be careful when using a wide angle lens for your landscape photography, that the distortion works out nicely. And last but not least keep looking, although you might think there is nothing. Photographing in the desert is the art of seeing.