The safest first tune is not the most extreme tune. Start with one handling problem, make one category change, test it on the same route, and only then move to the next setting.
Do not tune every slider because the car feels bad. Name the problem first: understeer, oversteer, wheelspin, slow launch, unstable braking, or poor top speed.
Use the same route for every test.
Write down class, drivetrain, race type, and assists.
Change one setting category at a time.
Tune in a repeatable order
A simple order keeps the setup from becoming confusing: tires, alignment, anti-roll bars, suspension, differential, then gearing.
Fix grip and balance before chasing power.
Use differential and gearing after the car already turns and brakes well.
Save a preset before making aggressive changes.
Know when to stop
A good baseline is easy to repeat. If the third run is harder than the first, the tune is probably moving away from the driver, not toward the car.
Compare lap feel and lap time together.
Keep stable tunes for weekly events.
Use aggressive tunes only when the route rewards them.