Hi Pandora.
I journal most days and I use a lot of bullet points which chart mundane events, weather, facts I've learned and daily tasks as well as a daily three point mood monitor thing.
I started doing it because I have difficulty with short term memory. Journelling helps me to observe patterns and reminds me of what my inner self needs to focus on.
I use a daily tarot spread and bullet point the main themes. I find that it is a very practical thing to engage in because it prompts my intuition to whatever I'm wanting to focus on that day. I also do a gratitude list.
In regards to people reading my stuff, the way I journal in my paper journal is so boring that I'm not worried and I throw most of it out when I'm finished anyway.
I use creative writing and I write short stories which read like children's stories if I'm needing to hash out deeper mental thoughts or honor deeper feelings. If anyone bothered to break into my room and read it, they would be reading children's stories lol.
However they choose to interpret it is up to then because it's art, people will interpret it in their own way. It's my creative right to express myself as I see fit in my own personal journal, it's purpose is to give me freedom to explore all manner of things in whatever way I want. If people take what I've written in a private journal as my gospel truth then perhaps they don't understand the nature of journals and creativity very well, life is a constantly moving energy flow and journals tend to reflect that.
Well.... That is at least my perspective on things anyway
My sister has a visual arts journal, which serves a similar purpose for her.
If you have a creative medium you have an affinity for you could try journelling with that medium.
I throw a lot of my writing in the bin when I no longer need it. I only keep the stuff I like from a creative perspective that I might like to turn into a children's book one day. I have no issue letting go of a vast majority of the stuff I write. In fact I find it sort of fun, it connects me to the cycles of nature and change. It's a physical way for me to honor those cycles.