People often disregard the importance of parking properly. As long as the car would fit and parking spaces are available, nothing else would matter to them. But the matter of likewise considering how you will leave the parking slot can be a hassle especially if you find yourself parking facing to a wall rather than a reverse position which makes it easier for you to get out.
Parallel parking is also something hard for most drivers to master. Actually, some people find themselves with dents and scratches mainly because they cannot properly fit in to these parallel parking spaces without being guided by another person. But in reality, the key towards being a good parallel parking is through backward approaches to which you can easily use the proper mixture when turning the front wheel.
It is not easy at first but after years of getting used to it, you may be surprised that you can squeeze your car into any slot especially if there is not good parking slot available. Some say that it is easier to park in parallel parking slots using the frontward approach. Depending on the distance and the space allocation, it does not necessarily follow.
Side mirrors are a great help actually. If you think of it, that is perhaps one reason why they are there; to aid you in backward parking in vertical or horizontal places. From the mirrors, you can easily calculate the distance you have from the gutter although it is still wiser to actually see it for yourself.