As I'm not pagan / Wicca (I'm Buddhist) I don't have a BOS, but I do keep a few books / Journals:
a Dream diary
a Meditation Diary
a book of thoughts (usually rambling on whatever topic is on my mind at any one time)
a Reiki Diary (recording how I feel after giving / receiving Reiki)
and a Remedy book.
This remedy book contains: herb tea recipes, aromatherapy recipes, natural remedies, soap and 'beauty' recipes, and a few household 'spells' such as a house protection bottle, etc.On many Buddhist retreats I've been on they encourage you to write your thoughts / feelings. I don't analyse mine too much - just record what I think / feel.
As for Tarot, I have a deck (Servants Of The Light deck*) which I haven't used for years
I got them out this morning, shuffled, cut three times and the 3 of Crescents (cups) came out.
Must find my books out to remember what this means!* http://www.aeclectic.net/tarot/cards/servants-of-the-light/