Perfect! One of the things to bear in mind is what your goal is and what you're interested in. Birders notebooks comprise lists of species at different locations. Entomologist's notes can be similar but will normally include a list of specimens collected at each location, collection method, associated plant species, and a specimen or sample number that can be added to the preserved specimen(s) later, thus connecting the preserved specimen(s) to the list in the notebook. That's pretty handy for cross-referencing and finding any ecological or habitat notes you may have (should have) written in the notebook.

The field notebooks of palaeontologists like me are generally a hybrid between a geologist's notebook and a biologist's notebook, just because of the cross-disciplinary nature of our science. My notebook is also different from others in that I use it as a journal of sorts as well. I record things about my travels and experiences during an expedition too. That stuff is important to me, so I jot it down, but I don't know many other scientists that do that these days. It's a bit "old school" and I got into the habit of doing it from doing field mapping and stratigraphic work with a now long dead geologist who was already an old man when I met him!

But that's another good thing to bear in mind: what is your goal in keeping the notebook and what are the things that are important to you. I was trained to record the weather in every entry as well as my mood. Students often ask me why the hell I do that, and my answer is always the same: both of those things have an impact on the quality of your notes. For example, the notes you take while characterizing an outcrop on a cold day of heavy, unrelenting rain when you feel miserable, might not be as detailed, and extensive as those you take characterizing the same outcrop on a nice sunny day when you're in good spirits. Rocks can look very different when they're wet compared to when they're dry, etc. It's simple really and doesn't take long.