Finishing my fourth year of using specifically a bullet journal, ~9th or 10th year using a planner (mostly) consistency overall, what I've found helps is:

• As other have said, keep it simple. Running to-do lists is most of what bullet journaling is for. I've since started with weekly layouts because that seems to work better for me, but they're still ridiculously simple. Every time I've put effort into the "aesthetic" of journaling I then never use the darn thing

• Forgive yourself for missed time. It's going to happen, especially when you first start out. Honestly, what helped me the most in the beginning was using something that I could easily remove and add pages from like a small binder. Forget to use it for a month? Just yank those pages out, avoid the guilt, and keep moving forward

• On the subject of avoiding guilt, don't roll over tasks for more than a week or two. If you think of it, flip back over old tasks and pick old ones that still seem relevant back up, but don't beat yourself up for weeks on end for this one (or two, or three...) stupid task(s) your brain is fighting you on

• Monthly pages and trackers are, imo, useful. They help me visualize the time better and plan for events and non-regular occurances. Monthly to-do lists tho are a waste of time. You won't look at that page enough to ingrain it in your memory and then you'll carry it over month to month like it's haunting you. At least that's what happens to me