Change enters into your life when you tap into your habits.
First step : assess your habits, notice them, make a list.
Which one do you want to eradicate ? Find a positive objective with a higher satisfaction you could have without this bad habit.
Then, introduce an habit in replacement of another.
Reward every little progress/success.
Log your progress.
Also try to repeat the scenario.
An habit comes into automation after 21 days.
Repeat the scenario as much as you like.