Journaling can provide a wealth of benefits on levels both personal and professional. What place does it hold in your life? What sorts of thoughts do you transcribe in your journal? What benefits do you personally derive from journaling? What more would you like to do with it that you don’t yet?
If you don’t keep up with your journaling—either at all, or as much as you’d like—then write about that. Write about what you’d like to do with journaling; where you see it taking you. Write about the variety of things you might journal about, and if you can, trick yourself into segueing from there into actually writing about them.