Pack lightweight, washable cloths plus a sweater for early morning game drives, a sunhat, sunglasses and sunscreen. Long sleeves and trousers in light-colored fabrics help discourage insect bites. Shorts for women are acceptable (but not too short). Women should carry a wrap to cover legs in the village and towns as revealing cloths can cause offence, especially in Zanzibar and Muslim areas. On the beach and within the confines of beach hotels normal swim wear (but not nudity) is acceptable. For climbing on Kilimanjaro and Meru, take thermal underwear, light layers, sweater, rain jacket, good socks and sturdy boots.
Bring film and batteries for your camera with you. Protect your camera from dust and keep equipment and film cool. It is courteous to ask permission before photographing local people. If you intend to take a lot of people pictures, be sure to bring an instant camera with you so that you can leave a picture with people you photograph.
Most of the better hotels and lodges will spray rooms and provide mosquito nets, but do bring your own insect repellent sprays.
A flashlight is always useful.
There will be no television or radio in most places, so you might want to bring a little short-wave radio or Walkman if you want to keep up with world events or listen to some music.
Remember that safari vehicles and light aircraft have tight limits on the size and weight of luggage carried. Depending on your itinerary it may be possible to leave some luggage in your hotel for the duration of your safari.