While I have nice handwriting and some experience with hand-lettering, I knew if I got too precious about layouts and color-coding, I'd be less likely to actually do it. After I was a month into bullet journaling, and was sure it was a habit that was going to stick, I felt OK adding some color. Then a couple months later I started doing more involved weekly layouts. But it's totally, totally fine to take a more minimalist approach. (I also only use color on the headers/flair so if, say, I forget my green pen, I can just use pencil as a placeholder.)