Medication like Antidepressants (SSRI – Selective Serotonin Reuptake Inhibitor) helps to boost Serotonin level.
But there are natural ways to do it without medication. There’s this strange herb called "St John’s Wort" – it is said to be more effective than Prozac. No, it is not for mild depression only and ignore those sayings. In fact, it does help anxiety and panic-attacks as St John’s Wort works like prozac. Other natural ways will be exercise, diet, more exposure to light, etc.

The problem is that, even if your Serotonin is balanced… you have that "learned behavior" in your mind. You need to break that initial cycle to destroy that learned behavior – Cognitive Behavior Therapy (CBT) does this. A technique that you can use without CBT will be Distraction… There are several other techniques to help cope them!
Ok, to use Distraction: Firstly, try to….

Extracted from Source.
References :
http://PanicAttackResearch.blogspot.com

Erika B.Hillard:Living fully with shyness and social anxiety, NY,2005

a lot: practical and informative. (Read the readers reviews on Amazon.com.)

References :

From panic to Power by LUCINDA BASSETT

In my opinion she is the only one out there who really understands anxiety and how to overcome it. She has been there and done that.. she really does speak to it. Before I found the method that finally worked for me, her writing was the only thing that approached having a clue what it was all about and how tocontrol it.
References :