I start with checking the strack. if it similar to the track i was racing at before i will keep the setup i have on the car.
If the setup doesnt fit for this track i will begin with checking ride height and softness and hardness rear and front. If i want to fine tune i will change springs, oil or someting like camber, caster etc. Depends how the track feels and then i know what to change.
But Tweaking is what i do after every run.