Portray your character according to that role's super objective in every scene. The super objective is the thing that your character wants more than anything in the world throughout the story. The super objective has a compelling emotional justification somewhere in his background. This objective is your character's defining emotion-driven pursuit that he stops-at-nothing for. Some scripts define a character's objective explicitly and others give the super objective implicitly. Define your character's super objective only by basing it on facts about your character that are written in the script.
Portray your character according to that role's objective in particular scenes. Your character has a specific objective in every scene where he appears. The objective for every scene is derived from the character's super-objective. Everything your character does in a scene derives from that character's desires in that particular scene. Your character's desires in a particular scene derive from and serve the pursuit of his super objective.
Use physical triggers to portray specific emotions. Close your eyes and recall vivid memories of emotional states that are the same as your character's emotions, or assemble fictional, but equally vivid, memories of those emotional states in your head. Vivid memories or visualizations bring you into the emotional state. Create a trigger when you reach the appropriate emotional state by performing a discreet bodily movement. For example, imagine your last fight with your roommate for your character's fight with his brother, and clench your fist tightly to store the emotion in that body movement. You can recall the emotion at will more easily by clenching your fist whenever you rehearse that scene.
Practice non-verbal communication by expressing your feelings with gestures and body movements. Focus on expressing feelings such as anger, excitement, anxiety and fear by the way your body moves. Focus on individual feelings for five minutes at a time. Practicing non-verbal communication improves your ability to convey characters that are silly, sexy, graceful or powerful because non-verbal communication helps animate your emotions for the audience.
Work on portraying physical sensations like toothaches, being out of breath, arousal or determination by recalling detailed memories of those sensations. Sit in a quiet environment, close your eyes and think of the last vivid memory you have of experiencing a particular sensation. Recall precise details of the experience to form a vivid recollection. Think about your exact location, actions, body movements, clothing, surroundings, colors, texture and what things looked and smelled like. This exercise will help you portray.