This is the most important advice I give in my workshops or when asked about journaling: Avoid censoring what you write. Your journal is a place only for you, where you can record and reflect on all that is happening or has occurred in your life as well as your hopes for the future. The content can be as wild, dark, inspiring, or joyful as you are feeling.
This is a no-judgment zone, except from you, but avoid doing that. No good comes from it and judgment inevitably leads to censorship. Be honest—brutally so if necessary—because that is how healing and growth happen. Then after some tough love, be gentle and kind with yourself and all your flaws, remembering that you are only human after all.