First, I laid the dress out in a circle. Then I folded the last layer to find 4 equal distances, and pinned those 4 points. Imagining the circle dress as a compass rose, I then pinned the 4 points to North, South, East, and West. See:
Then I took the half-way points of what was left, and pinned them at NE, NW, SE, SW. See:
Then, I took those half-way points, and pinned at NNE, ENE, NNW, WNW, SSE, ESE, etc.
Then I just kept going like that, pinning, sometimes folding and pinning until it was all pinned down and ready to be sewn. 75 pins is "all" that it took.
As I pinned, Wyatt played next to me and we even took a couple snack breaks for him. Here's my view during a snack break: