I reverse in all the time.
It really is only a matter of knowing how to position your car in front of the space right before reversing, and also getting used to the movements you see in your side mirrors as you're reversing and your car is turning into the space (I know some people prefer to look back while doing it, but that's actually harder for me for some reason). You just keep looking in both side mirrors back-and-forth until you see in your left mirror that the car on your left is parallel to your car (and there's enough space for you to get out), and same thing with the right mirror and the car on your right.....then you straighten up and back right in.
It does take some getting used to when you first learn it, though.
I'm still horrible at parallel parking. If the space isn't at least two-and-a-half car lengths, forget it.