well I don't know what tire pressure you were at already, but I can give you general advice.
There is a few things to know about tire pressure before you go play with it too much. You can control the cars handling 'feel' by adjusting the front or the rear or both. Depending on what you are feeling. Too high a tire pressure can cause pre-mature tire wear/blow outs, too low pressure the tires will be sloshy and roll over on the sidewalls. (to prevent this, people use stretches/low profile tires, because it creates a stiffer sidewall) Another very important thing to remember when drifting/racing is that tires heat up. This extra heat causes tire pressure to rise. From my experience, the fronts raise 2-3psi and the rears about 5-7psi depending on the day/track/speeds im going. Its VERY important to be consistent with car settings if you are going to advance your driving skills. This heating factor for air pressure is why top drivers: a) do burnouts before a session, after tires have cooled since last session (b) have a pit crew guy check PSI after every run (c) run the same exact tires every time. The less variables you have to 'consider' what is causing the handling issue, the easier you can overcome it. For now, learning to drive and take the psi rise into consideration on your own will make you better prepared when you get more into the sport. Its a lot of trial and error to find out how you like it, but once you get it down, its like routine and stupid simple.
Adjustments (the psi changes are suggested to start with, once you try it, feel free to only change by 1-2 psi if you want, its all your choice of course):
If you are oversteering way too much:
- Steering input feels responsive, but the rear is way too slippery
**Lower rear tire pressure ~5psi and try that, then re-evaluate
-Steering input feels responsive, but the rear is way too grippy
**Raise rear tire pressure ~5psi and try that, then re-evaluate
-Rear grip seems perfect for your cars power (you can slide and control it fine), but you are getting understeer a lot, or the car is slow to respond.
**Lower Front tire pressure ~4 psi and try, re-evaluate.
--Rear grip seems perfect for your cars power (you can slide and control it fine), but your front tires are rolling over on the sidewall and that is causing understeer. If you aren't sure, you can color/paint on the tires sidewall- do 2 or 3 runs, and check to see if it is getting rubbed off far down on the sidewall.
**Raise Front tire pressure ~4psi try, re-evaluate.
General rule is that lowering tire pressure will add grip, to a certain point, after that psi is reached and you go lower, it gets sloshy and handles like crap. Adding tire pressure MAY add grip IF you are below that point, other than that, normally you will lose grip in the tire. Add too much and you can blow them out quickly. If you have to add that much air that your blowign them up or running them at like 60psi- get skinnier tires or smaller wheels (goto 14s instead of 15s, or 15s instead of 16s).
Surface, tire brand, tire model, and temperature all play a roll in the cars handling so each day might be slightly different. Find a psi you like to start at (mine is 32 in all 4) and then do a 2-3 runs and think about whats going on. Its easy to get hung up on changing tire pressure- thinkin it will solve the drivers problem, but it can make a big difference in a driver struggling, versus controlling the car.
On top of all this, if you have adjustable suspension, you have even further ways to change the handling of the car. Sometimes you like the way the tires are wearing and gripping and heating up, but you want a little more this or that, the adjustable coilovers are great for that.
Good luck, and sorry for writing a book, but should give you a great start.