A very common first request of a potential Dominant, either online or offline is to have you start a submissive journal. If you've never kept a diary then this can be a daunting task. Having to write openly and honestly about your feelings and experiences can have a huge impact on your submissive and personal development. A submissive journal is all about you. Even if the journal is by your choice, or you are not currently in a relationship, a submissive journal has it's place.
When you are first directed to write a journal you should decide if it will be a physical journal, a digital journal or an online journal/blog. This can be determined by the Dominant or you can be given free reign to decide what to do. If in doubt, ask your Dominant. Respect your comfort level when you choose a method. If it is a physical journal, decide where you are going to keep it, whether it needs to be locked and if your Dominant will be reading it. Writing in an online journal usually means that you have potential to have anonymous readers read your blog, or you can password protect it.
The first post always seems to be the hardest. You stare at the blank page and nothing in your head seems to jump onto the page. So much is waiting to be said, but nothing can be said till you know what your journal is going to do for you. Is it going to be where you do writing tasks given to you by your Dominant? If so you probably don't have to worry about what to write about since it will be decided for you. A way to get over that first hurdle would be to introduce yourself to your journal. Write about who you are, the relationship you are in or would like to have and some of the thoughts you've had about submission that you'd like to answer someday... if not today.
Once you get your first post under your belt you can dig down into what you want to get out of your journal. This is your place. It can be private and intimate or open and wild. No matter what you end up writing, be honest with yourself. Make it yours.
Oh and if you get to a point where you need some help with topics, head on over to Submissive Journal Prompts and answer a thought or question from there. I have over 700 there so you may never run out.