The opportunities to photograph wildlife on safari are exceptional. You do not need to be an expert to capture a quality picture.
For wildlife photography, a 200mm lens is the recommended minimum. I travel with a Nikon camera body, a 70-300mm lens, a wide angle zoom lens, and a compact, HD video camera. Make sure to carry your expensive equipment in a well sealed bag to protect it from the elements. (No plastic bags during gorilla treks.)
Having appropriate storage for hundreds, if not thousands of pictures is essential. For still photography, I recommend an SD card with 16GB of storage. For video, I would recommend SD cards of at least 32GB.
There are also small, compact devices capable of storing a large amount of picture and video. These are a good alternative to packing a bulky laptop as a back-up storage device.
Have at least one spare, rechargeable battery for your camera. Most camps and lodges have the capability to recharge your electronics, usually at one specific charging station. With that in mind, at the end of the day, everyone in camp will want to charge their batteries, tablets, laptops, kindles, etc.
With so many opportunities for picture taking, it is easy to get caught up in experiencing your safari through a camera lens. Take the time to put down the camera and simply enjoy the world around you. Allow your senses to imprint a picture into memory where it is guaranteed to last a lifetime.