Fight scenes require careful planning and diligent practice.
Fight scenes can be quite challenging for actors. An actor must execute a complicated series of moves, giving the appearance of harming another person or getting hurt himself. His character might have to appear to sustain serious injury or even die while the actor stays safe. Doing all of this while staying in character is a complicated ballet which requires careful planning and diligent practice.
Eyes
Your eyes are your most important tools to act in a safe and convincing stage combat scenario. Whether you are training or performing, look around the area to make sure that it is clear of nails and other obstacles and that all actors and props are in the proper place before fighting. Use eye contact between each move or sequence of moves in a fight scene to prepare both partners for the next punch, kick, choke or other move. A quick glance can coordinate both partners, synching them up to make the fighting look more realistic and keeping the action safe for everyone.
Breath and Tension
Although your character may be tense, it is important for you to remain loose during the fight. Practice the fight scene at a comfortable pace, staying loose and relaxed while you learn the sequence. Breath normally during the whole sequence of the fight scene. Gradually build up speed until you can execute the whole scene at full speed without tensing up or getting out of breath. This will allow you to deliver your lines with the proper control and volume. If you start too fast, don't breathe properly or don't relax during your fight, you won't be able to really sell the fight, since it will be a strain just to produce the correct sequence of movements.
Fight as the Character
It's easy to get wrapped up in the dance of strike and counterstrike, but getting too involved in choreography can lead you to break character. Think about your character before you go into the fight scene. Is the character a trained martial artist, soldier or other professional combatant, a street fighter, or an untrained person unaccustomed to fighting? Why is the character fighting, and how important is the outcome? Is the character's survival at stake? Is his honor on the line? Is he horsing around with a friend? What kind of physical and psychological state is he in? Is he feeling scared or confident, alert or addled, sober or intoxicated? Is he in good shape or poor shape? Know where the character is coming from, and use that knowledge to make the fight scene more convincing.