I usually have no problem getting five stars. But I always use freeform, so money isn't an issue. It can be done on limited finance, but its hard work!
I build the zoo completely before opening it. Exhibits, paths, foliage, food courts, seats, lights, everything. If it ain't finished, it ain't open! :laughing:
I also have a broad mix of species and biomes. I tried once using a small map for big cats from different biomes, and I struggled with my fame.:pinch:
So for me its about three things: variety, preparation and probably most importantly, MONEY!!!:lolol: The few times I have had a cash limit, its taken much longer to get 5 stars.