Why are you speaking?
Once you understand what has happened and what needs to happen, the next related question is, why are you speaking? Okay, this would seem to be pretty obvious. You are speaking because it's your job. The department head always gives this presentation on Mondays (or whatever the occasion is). However, have you ever sat in a meeting room for two hours and left wondering what the point was? The probable cause is a speaker who did not consider his purpose or ponder why he was speaking.
If you are a teacher, you are speaking to convey information to your students. If you are giving a sales pitch, you are speaking to persuade your clients to buy whatever it is you're selling. If you are giving an annual all-hands meeting, you are speaking to inform and motivate. Once you start thinking about all the reasons why people speak in public and give presentations, you will realize that for many different kinds of presentations, there is some element of persuasion involved. Our beleaguered department head at the microchip factory is trying to persuade upper management that he is competent to fix the problem, and that his department is capable of preventing it from happening again. During the annual all-hands, the president of the company is trying to persuade the staff to buy into the company's future by sharing a corporate vision and convincing them to persevere through difficult times (or not to become too complacent during good times).
Remembering that persuasion plays a part in most presentations will help keep you focused on conveying your information in the most lively and useful way possible.
Where will you be speaking?
The particulars of how you convey this information will depend on the physical setup for your presentation. There are nearly limitless venues for presentations, so avoid the mental trap of thinking only about the same space you always use: the classroom, the conference room on the third floor, the spare office at the end of the hall. Many of the most persuasive speakers of all time had no rooms (think of Moses, John the Baptist, or Jesus). These people relied on their message and the power of their voice. They mostly spoke outside, wherever they found people. And you might find yourself speaking outside sometimes also, a situation that has a huge impact on how well you can be heard, the physical space around you, and the distractions you have to compete with.
For example, let's say you are a minister who usually speaks inside a church, but one of your couples ask you to officiate their beach wedding. You agree, but once you arrive, you realize that you will be marrying the couple only 20 feet from the surf. The family and friends are gathered about 20 feet away from you, which would be fine in a church with a roof to reflect the sound, but with no roof, your voice will have a hard time competing with the ocean breeze and the sound of the waves. To make things more interesting, tourists and vacationers stroll between the dearly beloved and the waves, sometimes playing football in the water. These are a lot of distractions to cope with, and in this case, the minister has about two options: get really loud and compelling in order to compete with all the other activity and interest going on around him, or realize it's a losing battle, focus on just the couple before him, and get through the ceremony as fast as he can before the wedding party breaks into a fight with the drunken tourists who keep trying to sneak into the wedding photos.
The purpose of describing this scenario is to illustrate that we often become so accustomed to a single physical space that our whole presentation style adapts to that one location. Before you even start planning your presentation, make sure you understand the physical space where you will be presenting it: the school board meeting room, the high school football field, or the 12-person meeting room with which you are so familiar. Within this space, will there be several other items of interest competing for your audience's attention? Will there be a lot of distractions? If so, either try to think of ways to quiet the competition, or plan to keep your message short enough to get the point across before you lose your audience entirely.