If you are driving round the park you have to follow the one way system, straight on from the entrance and then anticlockwise around the circuit - but parking at the appropriate places to see the animals. I would turn off into the car park on the left to see the chimps and then cross the road to the bears and then the penguins on the escarpment. Then you have to go around the one-way pedestrian route to the corner of the white rhinos and bongos then back to the car park along the main road. Then carry on in the car to the hippos and cheetah area, then the Asian drive-through to the elephants, Indian rhinos and tigers, finally park by the Aquarium and butterflies. You have to do the central part of the zoo on foot for the sea lions, red pandas, gaur, giraffes and lions etc.
If you are on foot you can follow the same basic route (except for the drive-through of course) or you can go the other way around - which might be preferable if the weather is wet, as you can get more shelter that way. Hope this helps.