There are so many ways to journal. I use it to work out problems. I may make a mind map, or make lists of 100 such as 100 things about _______, and it's okay if things repeat, but it allows things to emerge. With mind mapping, an example is that I had a problem with someone, so I wrote each part of it down, wrote things around each part, asked myself questions, and things emerged like, yeah it's as irritating as I thought, and various possible solutions.
Another way to journal is to set a timer, 1-20 minutes, and when the timer is up, stop writing. Period. This can help things come out without getting overwhelming and triggering.
You can write letters to objects or feelings. I wrote a letter telling a feeling how sick of it I was and that it didn't get to have power anymore. You can choose something random, like a word in a book or a photo in a magazine, and do a freewrite about it. Or choose a bunch of random words in the dictionary or a book and a do a freewrite or a poem.
Most importantly, my journal serves me, not the other way around.
I write when I want or need to, I don't follow a schedule. I'm as messy or neat as I want to be. I have more than one notebook and use them for different topics. I have a three-ring binder and have different sections, so I'm not stressed about the container of a bound notebook and use loose-leaf paper instead, then put it where it belongs after rather than being stressed about it being in the wrong notebook, or take things out of the notebooks and put them in the binder.