Being centered means having a point of reference, a place to come back to when life stress pushes you off balance. I find the best way for me to find my reference point is to meditate and reflect. However, there are times where meditation is not an option.
In those moments I take several deep cleansing breaths. Big, deep, belly breaths. It helps to restore peace and calm and get your head right!
There are times that I think I might lose it.... the key is to shut down the negative and bring in the positive and center your mind.