I thought I would post an article about how I prepare my talks.
The starting point is reading up on the subject and since I have over 2,000 books on Military History in my study, plus hundreds of electronic ones on my computer, I normally have everything I want. If not, then I do some research online.
I set up an electronic folder for each talk, and copy as many relevant pictures, maps etc into it that I can find. I modify some maps or diagrams of battles by taking out all images of troop positions and movements, then I can use the same map to show various stages in the battle. Some images just go straight in, others may take a week or more of modification.
I begin to create the talk on PowerPoint and as I do so, create a script as a Word Document. The talk will go through many modifications during its preparation. I tend to put everything of interest into it then, when it is complete, practice it to see how long it is. If it is too long I go back over it to see what can be cut out. I may well do this several times before it is right.
When I actually give my talks, I do not use a script or notes, but rely on the slides to act as a prompt for what I am going to say. I therefore make sure that the caption or other notes on the slides is sufficient to give me that prompt. Reading the script a few times beforehand also helps.
I use a remote slide changer, which doubles up as a laser pointer to assist in making sure that the talk flows smoothly.
Finally, when I have given the talk, I always ask for questions, which sometimes lets me mention additional matters which I had to cut out to prevent the talk being too long.