Treat the steering wheel, gas pedal, brake pedal as individuals who don't like to talk to each other.
If you're turning then you shouldn't be on the brakes or the gas. If you are going straight well you should be on the gas
If you are braking then you shouldn't be on the gas or the brakes.
This isn't true for pros like CivicSiRacer but should be the rule for first timers/newbies.
And slow the F-down! if you're understeering through the corner slow down by 5mph or more and hug the inside of the corner.
Lastly look ahead so you know whatt's coming up and you are not reacting to what's coming up but proactively setting up the car or settling the car for what's coming up.
I went from a 32.0x run in one run to 31.0x just by settling the suspension and not upsetting it and I'm by no means fast.
For example there was this one SE-R (new one) and he was understeering like a mofo around the clover leaf loop. So next time he came up for his run (I was the starter) I told him slow to what it feels like a crawl through the whole turn. He listened but he was on the gas as soon as he passed the apex so he was still coming out wide.
On his next run I told him don't get on the gas til your out of the turn and heading straight. He shaved 3 seconds total off with that. Then during the fun run I checked his tire pressure and it was at 52PSI! I told him to drop that bish to 45-44 and he shaved another second off and his fastest during the fun run was 34.9x. From a 37.9x that's not bad for a first time autoxer