No matter what it is you are trying to quit I found from personal experience that it is important to distance yourself from not only what you are trying to quit, like cigarettes or whatever, but from the people who might trigger your addiction and make you crave to do it again.
It's easy for me to stay away from alcohol for example when I am by myself and with other sober people. All it takes for me to slip is for a friend to innocently buy some beer and offer me one. What I need to do is tell those people to either stop doing that or tell those people they are not my friends anymore. Sometimes you have to go even further and tell family that too.