The place to begin any planning for a speech is with your audience. If you know your audience, you can better adapt your message to them. The process of getting to know your audience is called Audience Analysis.
You can gather insights and information about an audience in a number of ways, including
...Observing the audience before you speak
...Interviewing prospective audience members, past speakers to this group, and group leaders
...Reflecting on what you already know about the audience and making inferences
...Conducting formal questionnaires, informal surveys or telephone interviews
A typical audience analysis will gather information from all of these. But what type of information and insights are most helpful to a speaker?