A generic board structure
Since board-to-Pin topic match matters to ranking, sorting everything into a few broad, catch-all boards dilutes every Pin on them. A specific, clearly named board helps its Pins rank for the searches that match them.
A description written like a caption, not a search answer
A vague or casual description misses the platform's real advantage: matching Pins to specific search intent. A description that reads like it is answering a real search query performs far better than a generic one.
Judging a Pin's performance too early
Since Pins can keep earning traffic for months, checking performance a few days after publishing and writing off anything that has not taken off yet misjudges how the platform works. Many Pins take real time to find their audience.
A square or landscape crop instead of a vertical one
Pinterest's own data favors a tall, vertical format over square or landscape. Defaulting to whatever crop is already to hand, often square because it gets shared across other platforms, leaves real reach on the table for the sake of a little extra design work.