[AussieRacer]

Tyre pressures can play a part, but unless you are talking about variances of 2-3 psi on semi-road tyres it isn't a huge change in handling. Tyre pressure are just one setting on a whole car setup. Obviously in standard cars it is pretty much the only setting to play with, but with adjustable suspension a whole raft adjustments can be made based upon track, track conditions, tyre conditions, and driver preferences.

Best way to learn is first become comfortable with the car, and then play with the settings one at a time and in big changes, with accurate measurements so you can always return to the baseline. Big changes allow you to "feel" the difference the setting change made, so you can work out what does what, and what you prefer. Then you can fine tune to achieve the best result which is worked out by a combination of the seat of your pants feel, and the times. Eg. you might not like the feel of an oversteering car, but it might be a lot quicker due to the way you can put the power down, and it works the tyres. So it is a compromise.