purpose
Why you are speaking: to inform, persuade, instruct, entertain, reflect or build a relationship.
audience
The people listening: what they already know, what they need, and what they care about.
context
The situation: the time, place, occasion and how formal it is.
rhetorical situation
The whole set of things that shape a message: speaker, audience, purpose, context and the message itself.
register
How formal or informal your language is, from slang with friends to careful, precise language in a presentation.
signpost
A phrase that tells listeners where they are in a talk: My first reason is..., Now let's turn to..., To sum up...
coherent
Making sense as a whole: every part connects to one clear main message.