Select one monologue delivered by one character in a play you enjoy and with which you identify. The desired length of the monologue will often be set by the requirements of a given audition, but a good standard length is around 2 minutes. The passage you choose should demonstrate an interesting range of emotion, and should show the character going through some kind of change.
Read the entire play containing your monologue, and reflect on it until you have a good grasp of its plot and themes. You will want to thoroughly understand the motivation of the character you will be playing when you perform your monologue.
Analyze the scene, making a note every time a change--of the character's emotions, intentions, or relationship with another character--occurs. This will allow you to break your monologue down into sections, or beats.
Focus not only on portraying the emotions contained in your monologue, but also on transitioning between different beats in a believable manner.
Memorize the monologue until you know it by heart without having to reach for the words. Practice it over and over again.
Perform the monologue for a friend or an acting coach. Ask for an honest critique of your work. You will want to make adjustments to your monologue based on the feedback you receive.
Dress comfortably. Consider using a minor accessory, such as a piece of jewelry, book or hat to suggest your character without calling attention away from your performance.
Position yourself in the center of the spotlight to introduce the piece you will be performing. Let your personality shine through, and be friendly--nobody wants to hire a diva.
Block out the audience sitting before you and let yourself truly inhabit the character. Be sure to project your voice so everyone in the space can hear what you're saying.
Act as though you are surrounded by the objects and people in your character's world. You may be alone on an empty stage, but you need to imagine it as whatever environment your character is meant to inhabit. If your character is speaking to someone else, track that invisible person with your eyes and act as though that other character has a physical presence.
Cap off your monologue with a still moment, holding on your final note before exiting the stage.