Habits are little chunks of auto-pilot behavior that get burned permanently into your mind. Once you develop a habit, you can never really delete it.

Habits start with a trigger, which sets off your automatic behavior. They end at a pleasant reward that reinforces your habit.

Try to make a new reward that is similar to the old reward.
If it is a coffee habit, the reward is a warm beverage and an excuse to sit still and reflect. For that reason, a substitute like herbal tea would work.

Take an existing cue you have, but trick yourself into triggering a different behavior.
If you want to quit coffee, you could give away the coffee machine and put a box of tea or a glass of water on the countertop.

Reinforce habits with belief and community.
When we tell stories of our own lives of making the desired change, it creates belief. When others chime in, it shows that achieving changes is possible for everyone.