To perform a car headlight adjustment, turn the side and top adjuster screws in the headlight to adjust the horizontal and vertical alignments of the beam respectively. Then, repeat the process for the other headlight.
Locate a flat wall, and park the car in front of the wall so the car is 10 feet away from the wall and on a flat ground. Switch on and project the headlight beams onto the wall. To determine whether the light heights are at par, use a level. Tape the spot with the highest beam concentration on the wall, and repeat the process for the other beam. Use a measuring tape to determine the distance between the marks made, and tape the spots to which you intent to adjust the lights.
Once you have marked the spots, open the car hood to access the adjuster screws, usually on the top and side of the headlight. To adjust the vertical alignment, turn the top screw with a screwdriver, taking care not to set the beam excessively high to avoid blinding oncoming drivers. Turn the side screw to adjust the horizontal alignment of the beam. Repeat the process for the remaining headlight. Finally, sit in the driver's seat, and check if the lights are properly adjusted.