When trying to learn simple vocabulary in a manner similar to that suggested by Fluent Forever, I find that I have difficulties learning to spell words correctly with or without tildes.

I've been using the method suggested by Gabriel Wyner's book "Fluent Forever" to learn simple vocabulary. That is, I take a target word, add an image, and a pronunciation, and have cards that test whether I can produce a word given a picture, whether I can remember the meaning when given a word, and whether I can spell the word given the pronunciation. He doesn't advocate learning spelling with a separate card when learning an "easy" language or when you've already learnt other languages, but I'm a bit more cautious. I've also used his pronunciation trainers, with mixed results: 91% of the cards are mature by Anki standards, while I've got 7% suspended and 2% are young or learn.

Amongst the vocabulary I'm learning, the biggest challenge I've had is correctly spelling words with or without tildes. Looking at a deck of all Spanish cards I have, many (but not all) of the worst cards in terms of number of lapses are to do with spelling and the presence or absence of a tilde:

veintiséis, lápiz, película, azúcar, estantería, nariz, dieciséis, ayudáis, número, historia, latinoamérica, tócate, veintidós, maíz

My assumption is that I'm not able to hear the difference between a vowel pronounced with an accent (including those that don't need an accent mark because they're naturally accented), and those which are pronounced with an accent.

Maybe minimal pairs would help, but I don't seem to find minimal pairs for this.

How can I get better at learning how to spell Spanish words with or without tildes?