From the research, here are two interesting features that distinguish habits from other automatic responses.
- Habits are insensitive to short-term changes in the strength of contingency between the behavior and the outcome, and the value of those outcomes. This can be seen in the extreme in the case of addiction, in which addicts continue to perform the behaviors even though the value of the outcomes is lower than it was at first. In milder form, this can be seen in habitual use of Supercell games like Clash of Clans, in which the amount of labor between response and reward is very small in the early game, and very large in the late game.
- Decision making in humans impedes habit formation. If a human in a certain context stops and deliberates before choosing and executing a response, this event will not serve to strengthen the habitual context-response association the normal way. So if you want to make something a habit, do all that you can to remove the necessity of deliberation from the scenario.