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@rkoutnik: This is roughly my process FWIW…
I generally start with paper.
I have a notebook where I jot down ideas and bits of the story I want to tell. Occasionally this is .txt file but usually it's paper.
My next step is usually to translate the notes to index cards or post-it notes. One idea / bit of story per card.
The cards do not correspond to slides in a deck. One card might correspond to multiple slides in the end. Multiple cards might end up as one slide. What I'm trying to do is tell the story.
One of the reasons I use cards at this point is that it's a good reminder that they're not session slides. Another reason is that I find it much easier to get an overview of a few dozen cards on a large table than I do using a text file or presentation software. Much easier to rearrange, shuffle, tweak. Also very easy to review and tweak on the train/bus.
Once I get a sequence of cards that I think make a good talk - I give it to the wall, one of the dogs, my partner (if she's feeling generous). If something doesn't flow or it runs short/long I tweak the cards and repeat.
(I've not mastered the art of getting a good time estimate without speaking out loud. Some folk I know have. I envy them!)
I now have a talk - but I don't have a slide deck.
This is a very nice place to be. Even if the internet dies, my laptop bursts into flames, I lose my backup USB drive, the projector fails and an EMP device takes out every laptop in the room - I can still make a fair stab at doing a talk.
Next a slide deck.
I go through my index cards and write (usually on a computer at this point) a list of the main points and sub-points. If the talk is more story-ish I also note down climaxes / plot-twists.
Slap those points into a standard template in whatever your presentation software is. Come up with something entertaining and useful to stick on the slides. If you can't - delete the slide.
I try and remember that my slides are another communication channel so if I'm saying something it might not need to be on the slide. If something is on the slide I probably don't need to say it. Slides can provide counterpoints and commentary on the words. The words can provide counterpoints and commentary on the slides.
Give the talk again with the slides to wall/dog/partner/etc. Spot where it fails. Fix it. Repeat.