From experience around the Northern Territory trying to find my way across flat desert with no features. I have found that movement at night is much easier, for 2 reasons. The first is because it is much cooler and therefore your body will sweat less whilst moving preventing early onset of dehydration, secondly, I have found in such open featureless terrain the best way to determine direction use using the old faithful southern cross and the 2 pointers to confirm where south is. Even if you have a compass and a map if you can confirm your direction of the stars you can gaurentee success because the stars never lie! Its definetly not as accurate as a map and compass but it can help confirm your direction. Hope this helps