How to live comfortable in an over populated environment?
Impossible. Where there are too many people, there is violence and unnatural behavior. Humankind in a confined place seems to behave similarly to animals in confinement: the social engagement suffers and the natural behavior disappears.
Konrad Lorenz was an excellent writer, he also won a Nobel prize for his research related to animals/humans behavior and the analysis of society. I strongly recommend for you to read one of his master's book: Civilized man's eight deadly sins (you can download it from here:http://www.freepdf.info/index.php?post/Lorenz-Konrad-Civilized-man-s-eight-deadly-sins).
This is a brilliant exposition directly related to your question, for, in there, Lorenz explains how overpopulation is finishing the "natural" behavior of the humankind and how dangerous it is. He also compares human with wolfs in captivity and the changes in their natural social system.