The High Priestess is two, knowledge held; the Empress is three, the thing that grows. Three is the first number where something gets created (recall the minor Threes), and the major Three is creation itself: she sits between a wheat field and running water, Venus's sign on her cushion, not a straight line anywhere on the card. That's the mechanism — abundance isn't made, it's allowed to grow.
Where you'll recognise it: work that starts to have a life of its own, a relationship entering the phase where you feed each other, a body properly cared for, and the realisation that the best thing you can do is give it time. This card is about the senses and nature: eating, sleeping, touch, seasons.
Running well, the Empress is the most generous state there is: things grow on their own, you're fed too, people relax around you. Stuck, her problem is excess — giving until you're empty, protecting until the other can't grow up, or sinking into the senses and not surfacing. The wheat is for harvesting: nourishment has its season, and when the thing has grown enough you let go.