Find a great parking spot. Preferably, it should be slightly longer than your car. Tight spaces are tough, though they can be done. The car in front is the "target car".
Line your car up with the target car. A good guideline to follow is if you can see the (invisible) driver next to you, then you're lined up properly. Here, the back end happens to be aligned.
Shift into reverse, turn the wheel almost all the way to the right, then advance backward until your third brake light is lined up with the cars right headlight. See rearview mirror.
Once aligned, back straight toward that right headlight until your right front tire lines up with the left rear tire of the target car, as seen here.
Turn your wheels almost entirely to the left, and slowly advance backward. Get as close to the rear vehicle as you can without bumping it. Go slowly. Inch by inch if needed. Watch the curb.
Once you've gone as far back as you can go, straighten your wheels out and advance forward slowly until the bottom of the target car's back tires are barely visible over the hood of your car.
And there you have it! A perfectly parallel park job.