if you don’t know much about cars, there is no short answer for fh4 and nearly 700 different cars, seasons, weather, tons of different tracks, street/dirt/offraod, challanges and adventures you can do in the game.
its not possible to make cars not to slide at all…
for races its a question of balance the powerlevel and griplevel,
braking before the corner and find the right speed for the corner at the edge where the slide begin, no rapid movements on stick or wheel, try to be smooth, stay on the racing line, don’t accelerate to early on corner exit.
try different tunes, some are easier to drive and maybe slower, other tunes need more experience are maybe faster.
when tuning cars you can decide if you want more speed or more grip, depends on the class you tuning for, depends on the car itself and depends on the track you heading to, handling course or highspeed course… etc.pp.
you can download or make tunes to overtake in corners (more grip, less speed) or overtake on straights (less grip, more speed)
it is possible to write tons of tips about tuning the car, like longer gears = less slide but slower acceleration, etc.pp.
I would suggest you head to racing giudes, tuning guides, and guides how a car works. There is enough stuff all over the internet, also special guides for fh4.
its also possible to turn down the game difficultlevel and just drive very slow. you will be able to win for just some arcade action without getting very deep into cars and racing…