Think of the monologue as a story - it needs a hook at the beginning, a climax in the middle and the end needs to return the audience to the play. According to Google, another character must be present in order for the speech to be a monologue - that can be another cast member, a split personality or the audience. According to our class discussion that distinction is incorrect. A monologue needs no audience.
But if there is no audience do we then venture into soliloquy territory. A solili what now? A soliloquy is 'an act of speaking one's thoughts aloud when by oneself or regardless of any hearers, especially by a character in a play.' (Online dictionary). The obvious example is of course Hamlet's speech 'To be or not to be' and if you haven't seen it, watch the special BBC Shakespeare programme which included an excellent take on the famous soliloquy.
Back to class. Individual monologues were read out and as always in this situations there was a huge difference between style and length, content and purpose. It used to worry me that my work never sounded like anyone else's then I realised that was ok, different is good and really, lets be honest - there is no wrong in writing. I'd love to include my monologue here for you but .... I drew on some personal experiences and to be honest it's fine for strangers but way too close to the bone for people who know me.
However, all hope is not lost. I have the opportunity to record a monologue in a video booth as part of Pen to Print, Real People, Real Stories. The only problem is now I have to write another! How hard can it be?