

“Action alleviates anxiety.” -Sigmund Freud
“Use the relaxation to eliminate fear and tension that interrupts expression.” -Lee Strasberg
“The wrong kind of concentration is a stumbling block, and once you have removed it, you are better. If you can concentrate your genuine human powers of attention on fulfilling a concrete task in performance, you will be really good.” -Constantin Stanislavski
If you want to be confident, get focused.
Similarly, if you want to be relaxed (a must for any actor), concentrate on something. The famous acting teacher Lee Strasberg developed all kinds of exercises like this one and this one to do just that. One supposedly involved staring at a plate glass window, imagining you could break it with just your voice, and then trying to do just that.
One of the greatest baseball players of all time, Shoeless Joe Jackson, supposedly would stare for hours at a candle flame, to improve his “batting eye” and sharpen his concentration. (This could be apocryphal but it’s a cool scene in John Sayles’ awesome film Eight Men Out. And Shoeless Joe did hit .356 for his career.)
Point being, you don’t get relaxed by “trying to relax.” Instead, concentrate on a task with your whole being– the task could be removing tension in your body per the Strasberg exercise–and as a result of your concentration, you get relaxation thrown in for free.
P.S. – Hat tip to my friend David S. for the Freud quote above.