Lotus Padma - thank you so much for that link! It's *incredibly* helpful. I've spent a lot of time over the past little while collecting as much info as I can on animal symbolism, trying to better prepare for future cards, and that link is perfect!
rota - thank you so much for your advice. I've definitely been trying different methods to make the process a bit easier on me. I've taken many breaks away from creating the cards, just to unwind and to help clear my head. Now I think the most helpful method I've found so far is to simply force myself through them, trying to plow through ideas than to try to avoid working on it. I've now been trying to work on the cards in batches. Before I would put all of my focus on one card, working on it from start to finish, and it was a really tough way to go through each card that way. Now I started to sketch several all at once. (I also tend to have that short attention span and tend to try to multi-task, so going back and forth between ideas and cards definitely helps.) So I spend time on planning several cards, then sketching them all at once, then painting each of them. This way I always have something to work on, and don't get stuck when I've hit a wall on just one card. I have HUGE respect for everyone that makes their own cards! Goodness.
I've finished two more cards since: the Death card and the Six of Cups:
http://sobeyondthis.deviantart.com/gallery/32847081
I'm almost done the next one, which will be the Three of Wands