So I was thinking about the difference between a task list and a habit.
To me, it really comes down to task lists are a tool and habits are an action.
Task list are great. Whether you use your phone's built-in task list, a free app, or a paid app they can all be very powerful. I use Todoist with an annual subscription. Many people I know use, or used Wunderlist. My wife is the queen of bits of paper. And I have seen others that still have 1990's style pocket notebooks. I, myself, used Franklin Covey products back in that day.
Regardless of what you use, and if you are just starting out you should probably use something, these items are just tools. It is the action you put with them that starts to turn things into a habit. As a matter of fact, if you want to use a tool to help you build habits the first habit you need is to use the tool.
Once you have established the seed habit of using the tool you can figure out what works best in that tool. For me David Allan's "Getting Things Done" method. But just reading that book or his website did give me efficient habits. I needed to start the habit engine.
To "plant" the seed habit I looked at a few things and decided what would work best for me: Scheduled Reviews and Deliberate Thought.
Before even starting this process I knew I lived by my calendar. If it were not in my calendar it would not happen. So I schedule multiple times to review and reflect on what opportunities I had missed and taken to build my root habit of using my task list. I looked at what I added, evaluated it for quality and ensured that I would improve as time went along.
Reflection dovetailed nicely into the second part of my plan - Deliberate Thought. By doing these reviews, I was more likely to recognize an opportunity to use the tool and build the root habit.
Though it was easy to start this process, it was just as easy to skip it sometimes. But my calendar appointments brought me back into track. Your mileage may vary, but make sure that you have a means of getting back into it when life finally injects itself and you have to skip a few days or weeks.