How to practice mindfulness
Start by adding Walking Meditation to your practice.

Next, when you finish your meditation and are about to go on with your day, make a resolve to be mindful and try to keep that mindfulness as you leave the meditation.

Then start setting aside key times during the day when you will accomplish some activity mindfully.  For instance, it could be meal-time, or a break in which you take a walk or do your exercise.

Gradually expand that mindfulness practice to include other parts of your day.

You could also carry a mindfulness timer or app that will chime at regular intervals to remind you to be mindful.

Most important: don't get discouraged.  Getting distracted or falling back into old patterns is natural.  Mindlessness is a habit, and like all habits, it takes work and there is backsliding.