Step 1: Frame
A way to make then symmetrical would be to draw the design on paper and bend the wire tracing the pattern, especially if you have thick wire, but i didn't bother and i was pleased with how they turned out.
Fold in any sharp edges so they're not sticking out the middle where the wings will be attached to your back, but don't worry too much if they're short because the fabric will cover them.
Step 2: Fabric
**you might need 2 pairs if your wings are bigger**
As my wings are quite small (a good idea if you're planning to walk through doorways) i only used one pair, i started by cutting them in half along the seam at the top and kind of manoeuvred them to fit my frame. Theres no exact way to do it as it would depend on the tights and the shape of the wings, so just use your best judgement.
Tie them off with a big knot at the middle of the wings.