Dreaming that you are fighting represents something within you which is struggling to be acknowledged or in conflict with another part of you. It may also reflect an actual conflict you are having in your waking life which is transferring into your dream life.
Consider who you are fighting in your dream to see if there are any clues which you can use to identify the source of conflict. If it is a particular person you know, think of the quality you most associate with them and this may be an aspect of your own personality which is in turmoil.
To dream about watching other people fighting shows that you are unwilling to acknowledge the conflicting sides of your personality and until you face up to them you will not be able to resolve the feelings of anxiety the inner struggles will cause you.
If you dream that you are fighting to survive or in your dream fight you actually die this shows that you are stubborn and your unwillingness to change is causing you problems.