Unconventional decks like having anki cards for a whole piano piece or problem in a textbook might work

I have used Anki for learning bass guitar parts to songs, and I found this method: break a piece up into individual riffs or themes, make flashcards with the "[name of song] [riff or theme sheet music / tablature]". Add in flashcards that use cloze deletion on a list of how the riffs progress (intro -> verse -> ... -> verse -> chorus -> coda, for example, deleting chorus) and you have 10-20 cards, depending on complexity. I also threw in transitional licks appropriate to the song to bump the count up.

When testing yourself with the deck, have your instrument at hand. On riff cards, practice the riff for five minutes, then hit 'again'. Answer the other cards as normal - I originally planned to play the riff that was deleted, but I found it wasn't really necessary. I suggest responding 'again' to each riff card until you can play the riff first try.

The bonus of this method is it works out to ~1 hour of practice of your instrument. I found huge improvements because it ensured 80% of my hour was spent actually learning and improving rather than practicing well-known or ingrained patterns. My recall of songs from name was significantly higher too.

Normal flashcards should be all equally difficult: as easy as possible. The idea is to break everything down into atomic facts; this makes it so you can't short-circuit a difficult card by just memorizing the answer; by memorizing all the parts, you still have the whole.

In my experience, I've found this to not be as true as it seems. I originally had many of my cards as atomic as possible, based on what Piotr Wozniak suggests, but while I had each individual part memorized, they all seemed to hang loosely connected, without a vivid thread holding it all together. Two clear examples for me are memorizing chess moves and poetry: Originally I'd memorize poems line by line, with each line shown in its surrounding context to prompt me, and chess games move-by-move, prompted by the state of the board at that moment.

I later experimented with more coarse chunks, where a single card would represent an entire stanza of a poem, or 10 ply of moves from a high-tier chess game. The cards took longer per interaction, but only a little longer (since I didn't have to switch contexts, increasing short-term flow), and the relativly fewer number of cards needed to represent the information more than made up for the longer reviews. But the most important benefit was that things suddenly became much clearer for me. Instead of being vaguely aware of the contours of the poems, I would find myself reciting them wholesale in the shower, unprompted (even fairly long poems like Tennyson's Ulysses, which clocks in at 70 lines - which, by the way, I shudder at the thought of trying to memorize line-by-line, like I have some shorter poems). Suddenly, I would see an entire series of chess moves as being deeply interconnected, in a way I never noticed trying to memorize those same moves one at a time.

The main benefit I thought atomization would provide, namely that each element would be readily available for combination with other, seemingly unrelated ideas, I don't really notice much loss of. While each element is richly situated in an existing context, I can easily pluck that idea out of that context to join it with ideas from another, but the richness of the existing context makes it much easier to get a handle on that idea in the first place