I used to work in mass marketing for the consumer and then changing behaviour for the benefit of society.
Part of the puzzle is habit. But experience is another piece, Changing habits one by one works in the short term, but if you don't make it a positive experience in the long run your old habits will return.
For example I could say I will not go shopping at the malls. This may work in the short term, but you need to come up with a long term plan for you to not see it as a minus.
Because for many people its not about needing something, its the feeling of getting something different, about brightening up their day.
So if you find a second hand shop that you enjoy looking in, this can replace going to the mall.
Or you might meet people for a meal or cup of coffee, perhaps replace this with a walk and a thermos.
Whatever habits you're changing, make sure there are replacements which enhance your experience of life and lifestyle. (not the lifestyle you perceive others expect of you)