I think quite a few of us have maintained a tarot journal down the years - I have a section for each card in the deck and every time I do an intensive deck study I copy all I write into the Journal. I also find that studying many different versions of the same card gives a wider viewpoint and understanding of the card. It's interesting to see how my ideas have deepened down the years.
I originally kept a paper journal but ended up scanning it into the computer at intervals
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One thing that is useful is the 78 week card study in Using Tarot Cards - doing that study is a real learning tool. Also, the various Study Groups for the decks offer a chance to bounce ideas etc. and to expand the knowledge available on AT should the study for your particular deck not be all that widely posted on.
I used to copy readings and photographs of spreads into the journal but tbh after a couple of years I stopped. Now I would copy readings done with a new deck, but not with Ironwing.
Also, I would copy my daily draw into it, and sometimes write out a meditation that I had done with a particular card.
As you can guess, the journals are getting a tad hefty now