Aside from the obvious, such as making sure you're out early and late for the best light, it's very good, if you can, to have two bodies with you with two different lenses. I always try to have a mid-range zoom and telephoto to hand. This allows me to react quickly and either shoot wider, to include dramatic skies, or go in tight for close-ups. If you're shooting with only one body and have to change lenses, make sure you do so once the vehicle has stopped moving and the dust has settled. Another great tip is, if photographing animals in long grass, to introduce a delay in the Focus Tracking with Lock On menu. By moving the delay from 1 to 5, it means once you focus on your subject, it will help reduce the changes of the autofocus system refocussing on the grasses that are closer to you. I used this a lot on my recent trip to Kenya, especially on days when the wind was blowing the grass around a lot.