Footprints in the snow
There is a fairly well-known—possibly apocryphal—story about how an architect of some university campus buildings oversaw the completion of the buildings, but neglected to designate where the paved walking paths should go between the buildings' exits and entrances. Apparently the architect waited until the winter time, when the students and faculty trudged through the snow, leaving their footprints behind. In the middle of the winter, the architect visited the campus and measured where the footprints in the snow left the most well-trodden paths. The next spring, the architect had those pathways paved, completing the walking paths with the most optimal shortcuts across the campus.
This is a good metaphor for how a good, robust, healthy wiki can be formed—without planning or foresight—based solely on how the people use it, where they run into the most difficulties, where they need the most help, and providing the help that is most wanted, and the shortcuts most needed.
Maybe you don't know what needs to be fixed. Maybe you only sense, "It's not quite right. Something's missing." In that case, merely raising the issue leaves footprints in the snow for future contributors (possibly yourself!) to pave a new shortcut.