The optimum setup changes from track to track, so try to find a track you're comfortable with and just keep practicing, and experimenting with your setup until you find something reasonable to drive. Just keep doing that every now and then, then you can use that setup as a base for other tracks. But really, there is no such thing as a universal setup, every track will want different things out of your car. It might help to find a proven setup somewhere online, and start from there.
So a basic answer to your question, just find a track you are comfortable with yourself, so you know roughly where to brake and what line to take. For me, I'm most comfortable at Surfers Paradise, and do most of my testing there.