A safari isn’t radically different from other wildlife photography technically, so your current practice with birds and park wildlife is still useful. With your lenses, focus on making the most of what you have.

A few practical tips:

• Shoot a variety of compositions. Don’t only fill the frame with the animal; also try wider shots that show the animal in its environment for context.
• Bring plenty of memory cards. On safari, unexpected subjects can appear at any time, and you don’t want to be deleting images in the vehicle.
• If you’ll be shooting from a vehicle, a bean bag can be very helpful as a simple support.
• Bring a tripod if possible. Even if it’s not useful in the vehicle, it can help for evening stops and sunset shots when light levels fall.

In short: practice wildlife technique beforehand, be ready for both tight and environmental shots, and bring simple support gear plus enough storage so you can keep shooting freely.