I write down my experimental ideas, take notes during said experiments/shoots, write all my development notes, and paste examples inside.

General rule: if you’re focused on composing the layout of your photo notes, you’re worrying about the wrong thing.

I started off doing large format and for the first two years I diligently wrote down every exposure, filter, zone system development notes, and never once did I ever look back at it after the films were developed. Then I just wrote down what order I made the pictures and the holder number so I could track down any light leaks and so I could generally know if something might be n-, n, or n+ when developing by inspection.

But for digital?! Jeez. Who cares. That is what computers and metadata are for. Use that special notebook for writing you actual thoughts about what and WHY you’re photographing and not your meticulously manicured exposure notes.

Yeah, but what kind of pens and ink?

Everything you mentioned is in the RAW files metadata. No need to take notes.

I already use Photopills to plan the shot so I know the location I am shooting, direction of sun, moon and stars and time of day I’m shooting, even the fov of the lens I plan to use.

I have not watched that anime so don’t know the example you saw. I also was not into journal use when I was shooting more actively. I journaled other stuff and then changed formats as I went. So here’s some brainstorming.

Go do it for a while, and let yourself discover what you want in it, and then format it nicely as you figure it out. Put all your shooting data if you want, then decide after whether you want to pare down how much you write because it’s also in the metadata in the file. With digital it’s less important to write down the exposure values for each frame, so you could concentrate on trends for outings.

If you work with lights (continuous or strobe) sketches of the setup. Others might just back up and take a photo of the setup, or sit where the subject is and shoot outwards to see what the subject would see (or ‘see’ in the case of an object).

Ideas for notes outside of shooting: things you want to keep an eye out for because you didn’t notice them at the time (distracting objects, for example). As you read/watch learning material, takeaways and things to try, and then after when you decide how you felt about the techniques. Lessons learned for when you mess up, such as packing lists or checklists so you don’t drive somewhere short a critical piece of equipment.

Pick a nice notebook with guide lines and go at it! It can be random, or you can pre-pick certain pages for certain topics you’d expect to be taking notes for. But my tip for you is, don’t overthink how the journal is done, just go and do it, you will find a flow later on.