I free-write.
Instead of a traditional notebook, I really prefer a date book with some empty pages, and paragraph sized areas for each day.
I try to write down important things I realize about myself along with the daily record like "bathed dog"
I'm more consistent in some seasons. Sometimes I fill every spare blank spot with doodles, single words, or an unpunctuated stream of consciousness.
I like this style , there are two in the house. One at bedside, one in my picnic basket I haul my necessities around the house in. (Pens & pencils, diary, current notebook I'm writing stories in, oracle cards, hydrocortisone etc)
I really like the Katie Daisy Academic Year planner. It's very pretty, if your girl is a "pretty flowers" kind of person. It's 5x7, so it's B6-ish size.
It has a monthly calendar and horizontal weeklies, plus some random quotes and notes pages interspersed.
The other one you can look at is - https://www.personalplanner.com/US/ - different sizes and different layout options, lots of customization available.