Strangely enough, it took us a bit more time to get used to driving on the left side of the road than it did in the UK or South Africa. The main reason: lack of traffic.
It is difficult to wander off to the wrong side of the road in the congested traffic of London; you just follow the car in front of you. But when you drive around on empty streets, you sometimes forget which the right side of the road is and before you know it, you are driving on the right(hand) side of the road. Fortunately, there is so little traffic that our mistakes had no consequences. To illustrate the lack of traffic: when travelling from Aïs Aïs to Lüderitz, some 450 kilometres, which took us about 6 hours, we counted 98 cars, 65 trucks and 2 motorcycles.
Namibia has a few tarmac main roads, but most roads are gravel. For African standards, the roads are well maintained, but don’t be surprised that you will have to pass a few stretches where you bounce around in your car.
Even when the gravel roads seem fine, watch your speed. Renting a car in Namibia is expensive for a reason: hardly any rentals returns unscathed from a trip be it with a flat tire or as a total loss. We were fortunate enough to return with only a few dents from pebbles thrown at us by passing cars, but we have met people who had had four flat tires in one single day!
So drive safely and enjoy the mesmerizing landscape.