Calming the emotions will help you to think clearly. This is because negative emotions act as a bias to cloud your judgement.

What most people forget is that the bias of emotions is not merely in the physical sensation of the emotion, but also in the mental state. The mental state affects the very fabric of what you think and do, so its important that you calm your emotions in the first instance if there is to be true mental clarity.

Surprisingly, actually naming your emotions appears to have a profound effect in calming them. For example, if you are experiencing pain or fear, actually naming them as such will help to alleviate them, due to recognition.

Another technique you can use is "tapping" to re-establish positive energy flow. This is achieved by tapping on various energy points in the body and repeating affirmations of the mental state you wish to possess.

Perhaps the easiest and most basic technique however, is to simply take some deep breaths and let the air fully fill your lungs. Do this for about 2-3 minutes, and you should return to a relaxed state. You can also lie down with your back firm on the ground. This is particularly useful to stop you become angry and losing your mental focus.