Meditation makes a huge difference for me. I've tried a number of different methods, including using biofeedback devices but the most effective for me has been http://www.headspace.com. People who tend to have difficulty turning off the noise in their heads (such as myself) do well with guided imagery training such as that.
I've seen convincing results from amino acid therapy, but I sit among the skeptics on multi-vitamins. Without some sort of differentiating research for their products, this doesn't seem vastly superior to a recurring amazon purchase.