clear (one's) mind

To free one's mind of negative, intrusive, or chaotic thoughts; to achieve mental calm and serenity. Take a deep breath and clear your mind—you've got too many conflicting thoughts impeding your ability to think clearly. I always meditate for half an hour when I wake up to help me clear my mind at the start of the day. I've felt much less anxious ever since I started carving out time each day to clear my mind.