Whilst brushing your teeth. Stand on one foot and brush your teeth with the opposite hand. If you stand on your left foot in the morning, brush your teeth with your right hand. In the evening, reverse the process by standing on your right foot and using your left hand to brush your teeth.
Use a sand timer to measure time, observe the sand particles, it will help you stay in balance.
Advice – this exercise considerably strengthens your feet, it is not necessary for you to stand full Vrikshásana (or tree posture). If your feet hurt, touch the ground slightly with your toes. Continue for at least a month, it takes that long to change a behavioural pattern and for our muscles to learn a new skill.
Soon, you will be able to balance comfortably on either foot and brush your teeth with either hand. It will also harmonize the hemispheres of your brain.