Let's say you turn right to park in a spot but your turning radius sucks so you're at an angle and your rear right is really close to the car sitting in the space to the right.
Crank the wheel right as far as it'll go and crawl forward a handful of inches so the front of your car is equally close to the car on the right and you're parallel with that car but really close.
Straighten your wheels, reverse out all parallel to that car until your front bumper clears that car, then crank the wheel left and crawl in reverse a handful of inches, until the rear of the car is aiming in the other direction.
Straighten the wheel and crawl another couple of inches, until your rear axle is centered in the space, then put it in drive and pull right in now that the rear is centered.
You'll see some people try to straighten out but they just straight up reverse out of the spot and wind up back at square one, you don't want to do that, you want to use a bit excess room in front of and behind the car to essentially guide the offending axle into place, once that's done rest follows