Don't make it profound so that it becomes a chore: You can write what you want and figure out what matters later.
Just get started: Write down a few tasks you want to get done today. Consider how you can resolve some issues you're facing. Write down some ideas and get started.
Buy materials you like: If you hate your materials, you're going to be less likely to use them every day.
Don't worry if it is not artistic: It is a reflection of your life, and that makes it beautiful.
Start with one area of your life: Track your eating habits, or financial goals, or friend's birthdays, etc.