I find the interesting thing about monologues, compared to lines of dialogue, is that with dialogue the character's purpose is very clear. With a monologue, there is no single purpose to the character saying that.
Yes they want to get it off their chest, to hink aloud and let their thoughts wander. But it's mostly a device used by playwrights to explain something to the audience. Or show deeper, private feelings within a character.
Stresses and pauses are crucial. Choose the phrases which best sum up the character and how they are feeling, and emphasise those on delivery. Give a little pause after those bits so the audience understands it.
Monologues tend to be directed one of three ways.
- Either to a character not on stage, possibly a dead character, someone person who the actor could be speaking to in their own mind.
- To themselves. This might come across as telling yourself to do something. An internal conflict. At this point you're not concerned with anyone else on stage. Pausing is the most interesting thing here since its where the character is at their most unsure or insecure: they don't even know what to say to themselves.
- To the audience. Often a character would address a monologue out to the world. The verbal version of Twitter. This is where the emphasis of certain phrases is crucial.
Movement is an interesting one. If you're directing most of your words to the audience. Move. Engage with different parts of the audience. Make eye contact. You're often letting them into your soul.
If the monologue is directed towards yourself, I'd suggest moving a lot less. Or where you do Move, have a feeling that you're restricted in your movement because in this monogue you're trapped inside your own mind.
If the monologue is directed to someone else, where are they? If they are dead are they in the sky? Or are they a body on the floor. Or is it their ghost that you can see? You're welcome to place them behind or in he middle of the audience, just pick a spot and remember that the lines targeted towards that person, fire them in that direction.
(This is all my opinion.)