It seems that "just begin" is easier said than done but that may be because you are thinking too much. You can't help it. You start thinking about what colors to use, what technique or material to try, what to write, what papers to collage. Pretty soon, you're just overwhelmed. It's important to be aware of your thoughts at this time, be kind to yourself and take a deep breath. You can mindfully make a choice of just one thing. You can write your ideas on slips of paper and pull one at a time if you need to! I know that there are many creative ways to begin your art journal spread and if you are mindful of the first step, you will be able to "just begin" with more ease each time.