Safari vehicles and light aircraft have strict luggage limits, so pack a soft duffel rather than a hard case.
Bring neutral colours (avoid blue and black, which attract tsetse flies), a warm fleece for early game drives, a wide-brimmed hat, high-factor sun cream and binoculars you are happy to hold for hours.
Most camps offer same-day laundry, so three or four changes of clothing is plenty even on a two-week trip.