Try to get two laps in a row within one second. It does not need to be the fastest you can go, just consistent, predictable times. Then try to do that 3 laps in a row.. And then 4 laps.. and... well, you get the picture. Once you can just go on track and put 6 laps in, with full confidence, you are ready as one can be.
Just an example, i'm not a fast driver, i'm really slow. But last league race, i went from 16th fastest in raw pace in 22 driver grid to 9th in the finish. No mistakes = top ten finish (rain helped "a bit").
"To finish first, first you have to finish". A good driver is measured how many laptimes he can do in a row (with exception: 107% rule is not a joke, it really applies.. if you are within 107% from the winners pace, you have earned you place in the race...if you are not that fast you need to more laps until you get there. That level is with in reach of everyone, in my honest opinion)
Go to Time Attack mode to get rid of some variables but don't stay there too long. 10 laps is max, after that you will suffer (yuo are used to higher grip than what is simulated as "real life"). As a warmup or learning to drive consistently for few laps, it's a really good place to practice. Then get the hell out of there and drive with full simulation (tires do no wear or suffer thermal effects in Time Attack, tires are you most important piece of equipment, they allow acceleration and turning, so one need to learn to use them properly....Sooner that starts, the better...)
Learning the tracks, well, there is only one cure for that: drive.... It gets easier as the time goes by. At some point you can go to a totally new track and be within few seconds from your absolute best in first few laps.
Good luck, this is a hobby that very soon grows to a sport or obsession. Or both.