I can never really do the asthetics very well, so I just let the exhibits do the talking. I have my own little order for them as well...
When I make a zoo, I start with Desert, which leads into Scrub, which leads into Savannah, which leads into Tropical Rainforest, which leads into Wetlands, which leads into Grassland, which leads into Temperate Forest, which leads into Boreal Forest, which leads into Alpine, which leads into Tundra, which leads into Coastal, which leads into Reef, which leads into Pelagic, which leads into Benthic, which finishes the lot. It makes arragement easier for me.