Steve, read this, written by me about one year ago (referring to FC, but it's the same):
.... then I thought
"Well, Biggles will show some mercy on this poor soul and will turn "braking zones on". But no, the guy was in a bad mood and not only did he keep the settings (assist on, but I defended my dignity and kept them off) but he also chose ... Virginia Raceway

.
As it happened I was 1st in the "grid", so I just did the straight and parked to let them guys all by. Then, made a mess of myself the entire race and even parked again when they all ...
lapped me
For the full read you can check it here:
https://www.gtplanet.net/forum/showthread.php?t=112827
Biggles is SimcoeAce, the guy I chased for almost the entire race this time, so I would say I learned a lot since then, and you will learn also
A few notes:
1 - get rid of the braking zones line. It may look useful but it will in fact prevent you from learning the track as you should. Try lapping it without the line. If you struggle to find a correct braking point to a particular corner, check where does the "braking line" show up and turn it off again before you try it.
Without the braking line, the knowledge of the track increases dramatically. Not only braking distance in normal situations, but the effect of extra speed (because of drafting) or less speed, or the way you balance the car or the car gets un-balanced because of bumps or your own driving. Without the braking line you may feel you get "blind" in the first few laps, but you know what happens to blind people, don't you? They learn to use better all the other senses they have, in ways that we - not blind - will never understand or reach.
2 - No idea if you play with pad or wheel, but if with wheel, try putting the FFB to
"Low" and both sensitivities to
"Medium". This is what I use, maybe it is best for you also.
The steering in this game is a very delicate business but provides you of great feedback about what's happening to your front wheels and to the overall balance of the car.
If the wheel gets lighter that means most probably you are losing or without any grip and you must get it back (the pad users have an "assist" for this, an auto-correct feature that can be very annoying but that does the same, meaning ... looks for the lost grip straightening the wheels in understeer situations).
When the wheel gets "funky" when coming out of corners (pulling to one side, then the other, then one side again, sometimes lightly, sometimes violently)that just means the game is trying to tell you what's happening with the balance of the car. Oversteer in this game is very violent and difficult to control with a wheel, and you can get very nasty snaps that put you completely off-balance and make you lose a lot of time. Only practise /experience can help you here and some corners are very, very difficult to deal with, especially those that are long and envolve gear changing before the car is already going straight.
btw, one of my "nightmare" corners, is the long opening-radius right hander in Silvertsone just after the very tight left (approximately midlap, don't know the corner number or name). It is very difficult to hold the wheel steady and keep momentum there, something that is crucial because you are entering a "going-up" straight (sorry but my english is basic, I think you know what I mean)
About the pedals ... just keep a light foot, both for throttle and - especially -brakes. Braking is very hazardous and the braking distance depends a lot on how you do the braking (at least without ABS). I suggest, although it's not very "real", that you adopt a "pad" approach to the braking, at least until you get more comfortable and experienced. By "pad" approach I mean braking in successive touches to the "button", some longer, some shorter (blip-blip-blip-blip), the button being, in this case, the brake pedal.
If you use a pad, I lost a few moments of my precious life telling you things you don't need to know

and I suggest that you get advice from one of our many top pad drivers
