In building a good habit it's key you select a goal you want to achieve - and break that down into an activity you can do every day.
Your action should be defined so that it will take you less than 2 mins to do.
When you define your action so, then you will find that you have no barrier as it is easy to fit in a 2-minute action every day.
The reason why this 2-minute action will help you reach your goal is 2-fold:
The compound effect means when you have done your action for 1 year, you will have done it 365 times, that's 730 mins or over 12 hours of dedicated work towards your goal
The number of repetitions means your action is stored in memory and accessed without effort
The latter means you have reached a level of automatic reactions where your action is done without consciously thinking of it - and there you have your habit.