A great example of how good accessibility practices are often actually good usability practices for all. While the problems highlighted are most impactful on those who have challenges, I found every single alternative suggested improved usability for me as well.
Author Raghavendra Peri states:
According to the research conducted by Nielsen, it is not best practice to have a placeholder in the form field from a user experience perspective. This is because many users are confused by placeholders. In particular, people with cognitive disabilities tend to have issues understanding placeholder text because they think it is pre-populated text and will try to submit the form without entering their specific information.
TL;DR Don’t use placeholders! But for examples of what else to do, read this article.