Anxious thoughts can overwhelm, making it difficult to make decisions and take action to deal with whatever issue arises. Anxiety can also lead to overthinking, which makes you more anxious, which leads to more overthinking, and so on. How can you get out of this vicious cycle? Repressing anxious thoughts won’t work; they will just pop up again, sometimes with more intensity.

I really liked this read about Mindfulness.

http://insaneclopedia.com/1485/calm-the-brain-get-through-conflicts/

Mindfulness meditation has been found effective to help people avoid depression, among other things. It doesn't help stop depression; they recommend meditating when not depressed. IDK about anxiety, but may help. You should meditate when least anxious or not anxious if possible.

The color blue has a calming effect. It causes the brain to release calming hormones.