Freshly made lace is rumpled, springy, and stretchy. It's lovely, but is not even near its full potential. To achieve airy, drapey, elegant lace, we need to block it.
Once your project is finished, soak it for ten minutes in a bowl of warm water with a bit of Cot'n Wash or gentle detergent.
After its had a nice soak, stretch it out on a foam mat and thread blocking wires through each edge, weaving the wire through the lace openings. Then gently stretch the wires away from each other, stretching and opening the stitches of lace. When it was stretched out to the point where the lace looked nice and open, and the measurements are to your liking, pin down the wires.
I let piece dry over night, and then, voila! You have lovely, airy, open lace!