Journal privately so that it's honest

The key here is to make sure you won't be distracted if you hear a notification. This will make your journaling about you and your writing, and nothing else.

Keeping your journal private is important, even if you don't care whether other people read it or not. You may not mind if someone reads your personal journal, but if you don't trust that your thoughts are private, then you aren't going to be completely honest.

You may consciously or sub-consciously avoid writing about certain topics for fear of what others could think. This fear may hold you back from writing about stuff that matters in your journal.