Learning to be mindful takes practice.
Like anything you try to incorporate into your lifestyle such as eating healthier, cutting out carbs, or exercising, you must do it over and over in order to turn it into a habit. This is the same with being mindful although keeping track if you’ve been mindful for a day actually takes being mindful of when you were mindful! Ha!
Try keeping a small journal or note pad with you throughout the day and as soon as you catch yourself being mindful, write it down. Do this at least 5 times a day and watch as being mindful becomes a habit.