Slow your vehicle to a creep as you approach the perpendicular parking space.
Continue creeping until the front bumper of your vehicle is just past the painted line of the space in front of the one in which you're parking. This will be about when your shoulder is at the same point as the painted line of the previous space.
Turn the wheel to start moving into the space. Use your judgment to determine how sharply to turn the wheel.
Step on the gas slightly to move your vehicle into the space, straightening the wheel. Continue inching forward until you're all the way into the space.