Concentration. Try to stay focused and in character during your performance. If something goes wrong, try to cover without losing character. Remember, you want the audience to see the character, not the actor. So avoid laughing, looking at the audience inappropriately, etc. Try not to be self conscious.
Voice. A good voice is clear, strong, and expressive. This does not necessarily mean that you use proper diction and enunciate everything – most characters don’t. But your audience needs to understand you, so make sure you’re not mumbling or slurring or shouting so much that you’re not understood. Also, your audience ought to be able to tell something about your character by the way you speak. Make sure your voice is appropriate to your character.
Movement. Nervousness can make you fidget, rock, sway, or do any number of inappropriate things with your body. Work against this. Make your movement appropriate to your character and the situation. You want your movement to express character, not actor.
Here are a few guidelines to keep in mind!
Character – who is your character, what are her/his given circumstances
Objective – what does your character want and why; what is your character’s intention
Obstacle – what is getting in the way of your character getting what she/he wants
Person/people – to whom is your character speaking and how does this shape the way your character speaks
Tactic – what does your character do to get what she/he wants
Critical Moment- does your character experience a moment of realization that changes the outcome of their life or the story as a whole?
Address to the Silent Listener- your monologue should give insight and interesting information that helps your listener or audience understand the character and the text you have read.