Address it to someone
If you don't know how to begin, how about acting as if you're writing a letter? You can write to someone you know, someone you've made up, or to yourself in the future. Why do you think "Dear Diary" is such a popular beginning? It's helpful to act like you're telling this information to someone who really wants to know. Of course, you'll probably never send it to anyone, but you can go back and read it later and gain new insights about yourself.
