Ask HN: What product market fit strategy helped your startup?

I have a startup in the B2C space that lets users create animations quickly.

The reception is ok - people who use it in general love it. Retention is not so good. The people who like it a lot use it intensively for about a month and then drop off. The average user uses it for one time, produces an animation, exports it and never logs back in.

How did you tackle the product market fit / retention problem for your startup? How did you approach it? What metrics did you look at? What did you try? What worked and what did not?

Trying to learn. Thanks.