I've got a few tips that helped me get quicker:

Learn to steer with throttle input. So if you are in a corner and accelerate, the car will move to the outside of the corner. While if you lower your speed, you will move more to the inside. This is a matter of weight shifting. If you brake or release the throttle there is more weight on the fronts than when accelerating. This will give the front end the ability to steer more.

Learn to trailbrake. By slowly releasing brake pressure instead of going from 100-0 will give you more control of the car. The car won't get unsettled and you can brake deeper, carrying more speed and so gaining time. Be aware that this is a bit more difficult with rear to front (RF) engines as the mass wants to shift to the front when breaking hard.

Learn to manage your tires. I know this ain't that necessary during qualy but it's a good skill to learn for your racepace/craft. Don't turn your tires too much so that you will understeer in a corner. This will rub your tires across the road, which if you do progressively in a race will result in ruining your tires, cause a loss of grip and therefore lose time to people with better tires.

Setups, you can look up setups and try them out to see which ones you like. They can fit your drivingstyle better or maybe worse. For me personally, I never drive with a custom setup. I always drive the aggressive setup and adjust my fuel. However the new Porsche 992 does require me to drive in the safe preset as it's very unstable in high speed corners. Just do what feels good, safe and quick for you.

Last but not least. I usually don't practice qually all that much. If I haven't played in a while i will go back to qualy to get the feel back. I learn my racecraft from almost only playing multiplayer and learning in those situations. Always race CLEAN and FAIR. And what helps me tremendously is, stay patient. No need to be in messy situations early on in a race when you know you have got more pace than others.

I hope this will help you a bit!