Control Your Breathing - During panic or anxiety attacks you often hyperventilate. If you practice taking slow, deep breaths it can help settle your nerves. Try breathing in deeply, then hold for 4-6 seconds while gently telling yourself to "relax", then exhale completely.
Focus - "On what?" you say. Well, really almost anything "other" then on fighting the anxiety. Try, counting backwards, count the ceiling tiles, play a game of solitaire, do anything that takes your mind off your panic attack. Although this will help in the moment it really isn't a long term solution that deals with the root of the problem.
This Too Shall Pass - Even in the thick of a panic attack it can help if you try to remember it won't last forever. Panic attacks average 20 minutes long and few go beyond an hour in duration. Simply seeing the light at the end of the tunnel can help you make the situation feel less scary.
Don't Run - By leaving the location where your panic attack occurs can build an association with a particular situation, object or environment leading to the development of a phobia. Stick it out while trying some of the other tips in this article.
You Are What You Eat - If you are prone to panic attacks or anxiety you may be highly sensitive to caffeine. Try some decaf coffee, herbal tea, Coke Zero and cut back on the chocolate.