Keep a notebook for your characters. Dedicate two or three pages to each main character from your book, and write about things like their family, their birthday, their personality, and their favorite food. It's amazing how it makes your characters come to life.
Like notes about all their information, or the sort of enteries which they would write? I might give that a go. Have you ever tried doing character quizzes? I have a notebook for them, you look at what your characters would do in all these different scenarions. There's a great book called "What would your character do?" by Ann and Eric Maisel. It has all these different quizzes, and you pick options, and it says what that tells your about your character. It also gives you extra questions to ponder.
"Just like moons and like suns, With the certainty of tides, Just like hopes springing high, Still I'll rise." -Maya Angelou
well, both sound like good ideas, but i just write out miscellaneous information about them. like their birthdays, their hobbies, their favorite colors and stuff. maybe i'll post a page from my journal soon.
