In case you haven't noticed, I really love color! And I have a hard time with white space. However, for this page idea, I really wanted the words to come across without being in competition with a colorful background. So I decided to just use a black paint pen on this page. That's it. One supply. A black paint pen. And I'm really happy with how it turned out. It feels dynamic but not cluttered. The proportions on the person are off, but that's the first time I've drawn that, so it's ok. This page gives me the courage to try more "clean and simple" styles while still embracing my style.
If you're thinking you would like to start art journaling, I suggest you give the Get Messy community a try. Not only do you get weekly journal prompts, but it comes with an amazing supportive community of artists!