A book of shadows is a personal record of spells and beliefs, typical of sorcery and witchcraft. Each one is unique and private.
Steps

Step 1. Decide how you are going to store your Shadow Book
You can save it on your computer, in a notebook, a folder or in a journal. Many people use a binder because it gives them the option to change pages and create sections.

Step 2. State your beliefs
What do you believe in? What are your gods or goddesses, if they exist? Do you follow any law of witchcraft or sorcery? Do you believe in spell casting or just worship rituals? These questions and more can help you better understand your beliefs and put them on paper. (You don't need to do this if you don't want to)

Step 3. Write down any rituals or spells you have created, step by step
Data all your entries for future reference.

Step 4. Write the rituals and spells that you do as well as the influences, such as the lunar phases, etc
And the results. You can read them later and see how much progress you have made or what you could do differently.

Step 5. Include the songs, poetry, stories, drawings, etc
Whether they are created by you or by others. As long as it inspires or honors your god or goddess, it is valid.

Step 6. Every shadow book needs a reference page
At least the basics like the moon phases, their meanings, and some color charts.

Step 7. It might be a good idea to make a table of contents so that you can easily find things in your book of shadows
This makes finding the correct ritual, spell, enchantment faster and can help your ritual, spell, enchantment, etc. Work better.
Advice
- Look in craft stores for stickers and other things to add to your book.
- Computer-based shadow books aren't traditional (yet), but you may find this method considerably easier to maintain than other versions. Note-taking programs such as Google Notebook, Evernote, or Ms Office OneNote, are useful for this purpose. Remember to back it up, you might want to have a shadow memory stick. Since it is not a physical book, there is less chance that someone will find it. You can use password protection. If you need a page for your ritual you can always print it out and destroy it later.