Grab your favorite pen and find a comfortable spot and write something you'll enjoy reading in the future. It may be tempting to think of your diary as a possible published work, but this mentality can create an obligation to be insightful and to always find meaning in things. This obligation makes the purpose of keeping a diary obsolete. The purpose of keeping a diary is to freely express what comes to mind, without worrying about whether it makes sense or is revealing.
Your diary should be a conversation with yourself and a reflection of your thoughts. As I said in my previous post, “If you wait to have 'good things' to write about, your journal may remain closed for months. Journaling is an intensely intimate and personal process, and everyone has their own way of keeping a journal and expressing their emotions. The purpose of keeping a journal is to clear your mind, so you should write about whatever you have in mind, whether it's a recurring thought, a feeling that doesn't go away or a new idea.
Ask yourself some honest questions, such as if you need different notebooks for different purposes or if you prefer to use a digital recording application or a physical paper journal. I usually like to have a separate to-do list to write down all the tasks I want to complete, but I also write down in my journal some of the most important tasks I need to do the next day. Personally, for me, keeping a diary is an achievement in many ways, and that's why I want to help you develop the habit of keeping a journal. The key is to experiment continuously and wait until you start to enjoy the process of writing a journal.
I write my vision and mission very regularly in my journal because it helps me to keep them in my subconscious mind, to focus on them and to continue to reinforce them. If you judge what you write and are filled with self-pity or self-loathing, that goes against it of the purpose of keeping a diary.