I know quite a number of people who are inclined towards visualization techniques. I am not one of them and I really don't know very much about visualization. I've got enough on my plate with Zen practice as I understand it.
But, without disrespect towards those who find it useful, I did have had one exercise suggested to me that might be useful to others:
Sit down, close your eyes, rest your hands on your upper thighs, and call to mind that which is disturbing your life at the moment. Don't fixate -- just call it to mind. Then, with your eyes closed, visualize a great mountain as you inhale. Then, with the exhalation, just smile. Inhale with the mountain, exhale with a smile. Keep a strong focus on both inhalation and exhalation.
After three or four or five times, exhale one last time and then pat your upper thighs gently with the palms of your hands... eight or ten times.
And that's it.