Pack a while ahead. Most of the time you’ll be most comfortable in light, summer-weight clothes but do pack a warm jacket, socks, good shoes and a rain jacket. Pack sunscreen – lots of it – and a hat and sunglasses. Make sure you have at least one cool shirt with a collar for sun protection. Stock up on insect repellent and, if you’ll be in a malaria area, ensure you have a cool, long-sleeved shirt and cool long pants for evenings. Bring good walking shoes.
If you’re spending time watching game, you should try to wear reasonably neutral colours but, really, you don’t have to look like an extra on the set of Out of Africa. You don’t need formal clothes, but you will need something pretty smart for exclusive hotels.