Photographing wildlife is similar in some ways to photographing children.
You either need to be really close to them or you need a long enough lens to bring them really close to you! Animals seen from a distance are not interesting unless you are photographing an extremely large herd.
Again, like children, you have to appear friendly and non threatening, have lots of patience and time, and realize that it's all about them - you cannot reason with them, beg them, or in the case of animals, bribe them.
Animals with young are dangerous.
Don't do anything that may scare them and if you see a young animal on its own, be aware that the parent is probably nearby.
Don't get between a baby and it's parent and don't get between a hippo and a waterhole.
Hippos kill more people than any other wild animal although you would never think that to look at them.
Only turn your vehicle engine off when you are sure you are in a position of safety and make sure that you have a clear exit route if you need to leave in a hurry.
If you are lucky enough to see wildlife up close, hang about and be patient.
They may be moving slowly (in the case of herbivores) but they are moving, and you may end up with a better view and vantage point if you are prepared to wait.
Remember to keep the camera steady as all camera shake on a long lens will be magnified.
Find a solid object (eg.
the window frame of your stationary vehicle) to balance the camera on and squeeze the shutter gently.