Breathing. Seriously.. we have become a shallow-breathing people, and that has a tremendous negative impact on our lives. Our lungs were made to be filled with oxygen, yet we only seem to use that when we are severely lacking in oxygen, i.e. out of breath.

Get a book on Tai Chi.. Physical excersize is the best thing you can do for yourself, and there is probably no better place to start and end than Tai Chi. The first thing you will learn is how important breathing is. Every time you think about it, take a deep breath. But start from the bottom... allow your abdomen to stick out as the bottom of your lungs expand, then, almost like a wave effect, as the lungs fill more with air, allow your chest to expand, and the stomach to go in to compensate. Breath out the same way in reverse, out from your chest first, sticking your stomach out again, then as all the air escapes your lungs, your stomach will contract again. Do this right now.. just close your eyes, sit up straight, relax, and just... brreeeaaaaaaattttthhhh.

Any time you notice yourself breathing shallow, begin consciously taking full breaths in just this manner. The goal is to make it habit so that every breath is taken like this.

I seriously recommend getting a book on Tai Chi. I went to the library and got "The Complete Idiots Guide to Tai Chi and QiGong." The author is phenomenal, and he will tell you everything you need to know to get started on your own. Good luck!