just like anything else, if you want to be able to have the skills to be sucessful at something you have to practice. when it comes to dealing with stress, you hve to practice skills when you are not feelingstressed so that you are comfirtable using them whenyou are stresed. 

i want to talk about 2 breathing techniques to use. 

1 - cleasing breathing. this is a visualization in breathing. close your eyes and picture the breathing as it happens. in your body, you have all the "dirt" that is life causing you that internal stress. outside of you body you have fresh clean air free of the "dirt" of your life. so breath in through your nose, visualize the clean air that you have breathed in making its way through your body pushing out the dirty bad air. breath out through your mouth. visulize the bad air coming out and going far away from you tajiking all of those things in you that caused tat stress with it. continue his... in through the nose, out through the mouth... follow the path of the air in your mind as your body is cleased. 

2 - 5by5by5 breathing. this is about deveping control and feeling in control of your body. its very good when you feel things are moving too fast and need to slow things down and take control again. it is very simple. breatin for a count of five. hold for a count of five. breath out for a count of five. count in your head, on your fringers, whatever, just count it out and repeate the cycle. 

i hope these tips and techniques help.