I think some GTP members need a few more social ettiquette skills aorund here than driving skills.
Here's a few (if Jazza doesn't mind):
Do the license tests. The GT series is one of the most difficult, and yet, appreciated racing games there is. It's quite complex, and thus the tests will makes you a better driver in the game. Heck, it improved my driving skills in all decent racing games, and I've been playing them for about 20 years now.
Start with slow cars, move up to fast ones.
Appreciate that no two cars are really alike in the game. For example, the Audi TT doens't handle like a GT-R, because they have differing weights, measurements, power outputs, suspension geometries, et cetera. Thus, your driving style and setup preferences will vary a lot (or little) from car to car.
Some cars are very difficult to drive, others are rather easy. Search the forums to see what some people think about this car or that car. Some are nice right out of the box, and others require lots of tuning until you like they way it handles.
Patience, patience, patience. A virtue in this game, or any other activity. It took me 14 times until I won the Rome Circuit race in the GT-All Stars events...I was jumping for joy when I finally won it. That race could have drained my account to no credits (for all I cared), but I was very happy when I'd finally conquered it. So channel your anger and frustration into something useful, if the going gets rough.
If you find a race is frustrating you, then try another race or another car. Or maybe it's time to shut the game off for a little bit, and boost your confidence doing something else. Return to it when you're ready to take on the game with a different feeling than before.
Get some rest, eat well, breathe, blink. Sounds silly, right? Well, racing drivers are athletes, and athough you don't have to be in prime physical condition to play video games, having stamina to concentrate on anything (work, playing chess, painting, running, etc.) takes a healthy body and mind. So get out of your chair or sofa, take a stretch or two (touch your toes, move your legs, wrists, hands, neck, and torso) for a moment, and you'll feel a lot better. Drink some water here are there, take deep breaths here and there (or get some fresh air!). Oh, and blink...we don't think about that one very much; but you're eye-blinking rate decreases while staring at a computer screen or television set. You change from blinking an average of every 3 seconds to once every 45-60 seconds while sittling close to a monitor. This induces headaches, causes eye strain, and may actually decrease your hand-eye coordination. So blink...maybe not when you need to brake hard, but on the striaght.
Practice makes (nearly) perfect. Do some Test Runs before a race, and play with one setup variable at a time. You'll never figure out what's wrong if you change a lot all at once; you may get lucky here and there, or you'll just make a bad car worse. Remember, it's nearly impossible to make absolutely perfect laps over and over again.
It's just a game, remember.