The practice of mindfulness has two important pieces: 1) notice when you're distracted, and 2) return to the present moment, with spaciousness and compassion. We can't stop our thoughts and judgments, but we can form new relationships with them. Noticing is the first step in any awareness practice. We can't make changes from autopilot, but if we notice, we make more conscious choices.
Though sometimes we might notice and make judgments, "Joy, I can't believe you were lost in thoughts again. Pay attention!", our return to presence—through sensations of the body or sounds in the room—can be gentle and effective: "Joy, you've been ruminating. It's okay. Come back to your breath." Letting thoughts rest, letting judgments rest, for just a few moments. This cultivates awareness and compassion.
Mindfulness is a practice, not an end result. It requires a willingness to begin again and again; to drop expectations; to pay attention in a spacious, kind way. And it's possible to do this practice in small doses. Small changes have big impact.
I encourage you to practice now—in this very moment. If you feel a tug of resistance or not-enough-time, that's a clue you might really need this pause. Give yourself permission to just be; to listen to this short audio: