ASPIRE is a set of "best practices" for web development. It's mainly just a cool acronym, the advice itself was written after. https://twitter.com/aweyenberg/status/1180514636833214465
Don't just add some ARIA attributes and call it a day, actually try using your site with a screen reader and see if everything is still usable. Use colour filters to simulate color blindness and check if the site is still legible.
Is your entire site accessible over HTTPS? Practise safe password storage: use a safe "hashed and salted" storage method such as bcrypt. Require eight or more characters, but don't limit which or how many can be used.
Avoid asking, or at least allow optional or freeform entry, for the user's gender. Does your site still work using slow networks on devices with slow CPUs?
Make sure your site works as well on a weird tiny e-ink smartphone as it does on a giant ultrawide 4k monitor. Avoid rigid media queries, instead, use mainly dynamic layouts.
Don't collect any more data than is strictly nessecary. Don't add "antifeatures", such as DRM or user tracking. Impementing these recommendations may be difficult, as your profit model could revolve around them.