We've been writing a series of supplementary materials for Rosette Diceless that go into detail on some optional or situational play scenarios. Our most recent piece is "Tracking Personal Development," and it provides an option for laying down a plan for a character arc.
This idea arose from experiences in playtesting with a character that had a began with a vague purpose that crystallized over the initial months of play. As details of a future began to fill in, the player wanted ways to represent the character's progression and growth. This is one such way to do so.
You might instead want to build progression in a more explicit way--collecting certain pieces of information or Resources, revealing Secrets, and acquiring Traits or Skills. They can build a clear portfolio of your character's change to help demonstrate how it came about.
To read the rest, see "Tracking Personal Development" on the Rosette site.