Part of the pre-production process for a movie or TV show is to draw a storyboard. This converts the script (i.e. words) into images that will guide the actual making of the movie. It helps with set design, lighting, camera positions, etc.
I strongly recommend that you begin the process of developing a presentation by writing a script. Work out what it is you need to say to your audience to get the result you are looking for, whether that’s a decision, a sale, whatever.
Next, translate that script into a storyboard. What images do you want to support your words? You don’t need to be a great artist to do this. Rough sketches will do and there’s no need for lots of details. If you really can’t draw, write notes of what the image should be
You could do this on paper or in a notebook. You can get notebooks with pre-printed frames and you can download templates from the internet.
Personally, I find sticky post-it notes are best because they can be re-ordered easily. They also mean that if you make a mistake you can simply throw one away and re-draw it.
Once you have your storyboard then, and only then, should you open your presentation software and begin the process of creating the slides.
Below is an example of what I mean, created by Garr Reynolds at Presentation Zen.