Some more advice that I found useful on Wikihow.
This time on dealing with panic attacks, but I also think it works for any stressful situation:

Understand ‘Fight or Flight’.
Panic attacks are the result of the body’s “fight or flight” mechanism being triggered.

The problem is that the sub-conscious mind has overreacted to a perceived threat.

The reality is that we are not actually in danger even though we think, feel and act like we are.

Observe.
Once you realize that there is no “real” danger you can then focus on the experience you are having. Instead of feeling terrified become an objective observer of what you are feeling. Notice the feelings and sensations as they wash over you. By “observing” instead of “fighting” these feelings you reduce rather than increase the level of stress and conflict in your mind.

The process of observing is crucial because what it does is engages your rational mind. Normally during a panic attack the emotional mind takes over and controls you until the symptoms have run their course. The rational mind is nowhere to be found!

By turning yourself into an objective observer you allow your rational mind to function. It’s very difficult for the emotional mind to dominate if you are thinking rationally, so what happens is that the panic attack symptoms will start to fade away.