Here's some good advice from Daniel Bor, a cognitive neuroscientist, in his book "The Ravenous Brain: How the New Science of Consciousness Explains Our Insatiable Search for Meaning."
After enumerating some oft-heard ways to reduce stress (get enough sleep, exercise regularly, etc.), Bor says:
But eclipsing this list in the fight against stress is one simple mental exercise: meditation. This is often written off as being too esoteric and not sufficiently scientific, but it's been shown to profoundly help virtually any mental ailment, whether the person has a psychiatric condition or is merely suffering from the stresses and strains of everyday life.
There needn't be anything mystical to meditation. Although there are hundreds of different varieties, in my view meditation is at its most powerful in its purest, most basic form: An ideal meditation is one where you try to be as aware as you can of as little as possible.
We can focus on the world with our attentional magnifying glass set in two broad modes: We can mainly attend to the thoughts, ideas, facts, and so on that relate to other mental events or what our senses are picking up; or we can simply attend to our senses directly, passively absorbing the experience without thoughts.
We may be on a mountaintop and feel a calm, profound awe as we attend entirely to the delicate beauty of the vast snowcapped peaks surrounding us. Or we could enter a very different experiential mode and try to calculate the volume of each mountain as a mathematical exercise, infer what the name of each mountain is from various clues, and recognize the different geological features of the rocks around us.
In one state we have an open, quiet, passive perspective. In the other, we have a narrower, chattering mind, which isn't nearly so aware of our sensory experiences. This quieter sense of beauty is closely related to the so-called meditative experience.
Spending 20 minutes or more with nothing to do may sound pointless and tedious, but for those who try it, boredom, strangely, never seems an issue. It's as if, by intensely focusing attention continuously on the darkness of your closed eyes, a blank wall, or something equally minimal, you are telling your brain that this object is utterly fascinating.
...Over years of practice, regular meditation seems to permanently change the prefrontal parietal network, such that it becomes more pliable and efficient in its activity. And, again in direct contrast to what happens in depression and anxiety disorders, long-term meditation shifts the see-saw battles between the amygdala and prefrontal cortex firmly in the prefrontal cortex's favor: The amygdala becomes far less likely to activate, probably because the prefrontal parietal network is now so good at stepping in and taking control.
There is even evidence that long-term meditation increases the thickness of the prefrontal cortex, helping to protect against the natural thinning of this part of the brain in old age. At the same time, two months of meditation is sufficient to shrink the size of the fear-creating amygdala in previously stressed individuals.