When acting, it's important to lose yourself in a scene to an extent. Emotion is very fluid. As you act out a scene, try to let the emotional resonance flow through you naturally.  Allow your emotions to be fluid. If you try to constrict or control the emotional arch of the scene, your performance may feel forced. Try to really get inside your character's head and experience what that character is feeling. This will be easier to do if you have, as we discussed earlier, truly made an effort to get to know your character.  It is very hard to try to sustain or control emotion. While you should be aware of yourself and your body, you may find yourself suddenly being struck by a line. If you find your voice wavering or getting upset, go with it. Allow yourself to embrace your emotional response in any given scene. Humor can be a great way to shake up an emotional scene. As so many actors and actresses play up the drama, you can stand out in a scene by playing up the humor. Even in dark moments, there may be slightly humorous lines embedded in a scene. Try to focus energy on moments of levity rather than glossing over them. Your audience will appreciate a laugh between the tears and respond well to an actor who can deliver funny lines with ease. When playing an emotion, try to shake up the scene by playing that emotion in a non-obvious way. That is, play the opposite. This may make your character's emotions feel more intense for an audience.  If your character is angry, you may be inclined to yell or raise your voice. However, what about stone cold anger? You can instead convey anger through silence or quiet words. If your character is sad, maybe portray him in a manic light. Your character is trying to mask his sadness by appearing resilient and cheerful. When it comes to an antagonistic character, avoid playing the character as openly malevolent. Instead, play the character as polite, friendly even. Oftentimes, villains that appear cheery can be even scarier to audiences than outright angry villains. This may not work every time. You may want to do some trial and error in rehearsal to see if playing the opposite works. It's a technique worth trying, however, if you're acting out a dramatic scene. A scene should be somewhat self-contained. When acting out an emotional scene, do not try to change your character's emotional reaction too much in the course of that scene. Try to stick to one, overarching emotion and concentrate on that for the entirety of the scene. If your character is sad, play him as sad. If he's happy, play him as happy. You can change your tone, and the manner in which your character is playing an emotion. However, you should try to center yourself on one key emotion. When acting out a dramatic scene, you may be inclined to overact. Oftentimes, you lose control of your voice and end up shouting or talking too loudly. Try to be aware of the volume of your voice and keep your tone even and in control.  Even if your character is supposed to be angry, shouting too loudly can be a bad idea. You'll have a hard time controlling the tone of your voice, and how you're delivering the lines, if you're screaming on stage. Keep your voice somewhat quiet and even. Paying attention to physicality can help. If you feel your voice is inadequate when it comes to conveying drama, you may unconsciously raise your voice. However, tune into the physical when you feel you're not delivering in a scene. Do something with your body to convey feelings of anger, sadness, and frustration. This will help you feel like you're portraying your emotions effectively, lessening your need to overexert your voice. In an emotional scene, focus on what your character needs in that moment. Why is this moment important to your character? Focus less on the scene's significance to the overall story arch and more on its significance to your character.  If a character is arguing with someone else, do not focus on arguing against the other character. Instead, think of it as your character arguing for that particular relationship. Your character wants his relationship with this person to play out in a certain way. That's the fulcrum of the emotion in this scene.  Getting to know your character can really help here. If you perform a scene and feel so-so about your job, spend more time reviewing the work and getting inside your character's head. This can give you more insight into your character's needs, allowing you to channel them while acting.
Let the scene's emotions guide you. Incorporate humor. Play the opposite. Stick to one overarching emotion. Keep your voice in control. Focus on your character's needs.